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139-410: I2P started in 2003 as a fork of Freenet . The network is strictly message-based, like IP , but a library is available to allow reliable streaming communication on top of it (similar to Non-blocking IO -based TCP , although from version 0.6, a new Secure Semi-reliable UDP transport is used). All communication is end-to-end encrypted (in total, four layers of encryption are used when sending

278-472: A Content-Length field to specify the size of the message body to follow. However, the attacker then proceeds to send the actual message body at an extremely slow rate (e.g. 1 byte/110 seconds). Due to the entire message being correct and complete, the target server will attempt to obey the Content-Length field in the header, and wait for the entire body of the message to be transmitted, which can take

417-538: A denial-of-service attack ( DoS attack ) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network . Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled. The range of attacks varies widely, spanning from inundating

556-493: A heuristic routing algorithm where each node had no fixed location, and routing was based on which node had served a key closest to the key being fetched (in version 0.3) or which is estimated to serve it faster (in version 0.5). In either case, new connections were sometimes added to downstream nodes (i.e. the node that answered the request) when requests succeeded, and old nodes were discarded in least recently used order (or something close to it). Oskar Sandberg's research (during

695-496: A small-world structure. Other modifications include switching from TCP to UDP , which allows UDP hole punching along with faster transmission of messages between peers in the network. Freenet 0.7.5, released on 12 June 2009, offers a variety of improvements over 0.7. These include reduced memory usage, faster insert and retrieval of content, significant improvements to the FProxy web interface used for browsing freesites, and

834-443: A terabit per second . Some common examples of DDoS attacks are UDP flooding , SYN flooding and DNS amplification . A yo-yo attack is a specific type of DoS/DDoS aimed at cloud-hosted applications which use autoscaling . The attacker generates a flood of traffic until a cloud-hosted service scales outwards to handle the increase of traffic, then halts the attack, leaving the victim with over-provisioned resources. When

973-474: A DDoS, attacks may involve forging of IP sender addresses ( IP address spoofing ) further complicating identifying and defeating the attack. These attacker advantages cause challenges for defense mechanisms. For example, merely purchasing more incoming bandwidth than the current volume of the attack might not help, because the attacker might be able to simply add more attack machines. The scale of DDoS attacks has continued to rise over recent years, by 2016 exceeding

1112-650: A DNS name lookup request to one or more public DNS servers, spoofing the source IP address of the targeted victim. The attacker tries to request as much information as possible, thus amplifying the DNS response that is sent to the targeted victim. Since the size of the request is significantly smaller than the response, the attacker is easily able to increase the amount of traffic directed at the target. Simple Network Management Protocol (SNMP) and Network Time Protocol (NTP) can also be exploited as reflectors in an amplification attack. An example of an amplified DDoS attack through

1251-638: A HTTP pipelining DDoS attack on Sept. 5. 2021 that originated from unpatched Mikrotik networking gear. In the first half of 2022, the Russian invasion of Ukraine significantly shaped the cyberthreat landscape, with an increase in cyberattacks attributed to both state-sponsored actors and global hacktivist activities. The most notable event was a DDoS attack in February, the largest Ukraine has encountered, disrupting government and financial sector services. This wave of cyber aggression extended to Western allies like

1390-590: A KSK allows the document to be retrieved and decrypted if and only if the requester knows the human-readable string; this allows for more convenient (but less secure) URIs for users to refer to. A network is said to be scalable if its performance does not deteriorate even if the network is very large. The scalability of Freenet is being evaluated, but similar architectures have been shown to scale logarithmically. This work indicates that Freenet can find data in O ( log 2 ⁡ n ) {\displaystyle O(\log ^{2}n)} hops on

1529-409: A denial-of-service attack. Exposure of degradation-of-service attacks is complicated further by the matter of discerning whether the server is really being attacked or is experiencing higher than normal legitimate traffic loads. If an attacker mounts an attack from a single host, it would be classified as a DoS attack. Any attack against availability would be classed as a denial-of-service attack. On

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1668-850: A direct result of the anonymity requirements, the node requesting content does not normally connect directly to the node that has it; instead, the request is routed across several intermediaries, none of which know which node made the request or which one had it. As a result, the total bandwidth required by the network to transfer a file is higher than in other systems, which can result in slower transfers, especially for infrequently accessed content. Since version 0.7, Freenet offers two different levels of security: opennet and darknet. With opennet, users connect to arbitrary other users. With darknet, users connect only to "friends" with whom they previously exchanged public keys , named node-references. Both modes can be used together. Freenet's founders argue that true freedom of speech comes only with true anonymity and that

1807-509: A diversion to evade defensive DDoS countermeasures but all the while eventually concentrating the main thrust of the attack onto a single victim. In this scenario, attackers with continuous access to several very powerful network resources are capable of sustaining a prolonged campaign generating enormous levels of unamplified DDoS traffic. APDoS attacks are characterized by: Some vendors provide so-called booter or stresser services, which have simple web-based front ends, and accept payment over

1946-448: A few friends using the network to get the performance from having sufficient connections while still receiving some of the security benefits of darknet connections. This also means that small darknets where some users also have opennet connections are fully integrated into the whole Freenet network, allowing all users access to all content, whether they run opennet, darknet, or a hybrid of the two, except for darknet pockets connected only by

2085-423: A hacking tool to send these kinds of requests to attack a NSFOCUS firewall named Collapsar, and thus the hacking tool was known as Challenge Collapsar, or CC for short. Consequently, this type of attack got the name CC attack . A smurf attack relies on misconfigured network devices that allow packets to be sent to all computer hosts on a particular network via the broadcast address of the network, rather than

2224-547: A key. This is unlike most other P2P networks where node administrators can employ a ratio system, where users have to share a certain amount of content before they can download. Freenet may also be considered a small world network . The Freenet protocol is intended to be used on a network of complex topology, such as the Internet ( Internet Protocol ). Each node knows only about some number of other nodes that it can reach directly (its conceptual "neighbors"), but any node can be

2363-405: A large distributed, variable-size network of peer nodes. Some nodes are end user nodes, from which documents are requested and presented to human users. Other nodes serve only to route data. All nodes communicate with each other identically – there are no dedicated "clients" or "servers". It is not possible for a node to rate another node except by its capacity to insert and fetch data associated with

2502-485: A large number of smaller bugfixes, performance enhancements, and usability improvements. Version 0.7.5 also shipped with a new version of the Windows installer. As of build 1226, released on 30 July 2009, features that have been written include significant security improvements against both attackers acting on the network and physical seizure of the computer running the node. As of build 1468, released on 11 July 2015,

2641-434: A layer of strong encryption, and no reliance on centralized structures . This allows users to publish anonymously or retrieve various kinds of information. Freenet has been under continuous development since 2000. Freenet 0.7, released on 8 May 2008, is a major re-write incorporating a number of fundamental changes. The most fundamental change is support for darknet operation. Version 0.7 offered two modes of operation:

2780-547: A loop of paper at the sender. It takes more router resources to drop a packet with a TTL value of 1 or less than it does to forward a packet with a higher TTL value. When a packet is dropped due to TTL expiry, the router CPU must generate and send an ICMP time exceeded response. Generating many of these responses can overload the router's CPU. A UPnP attack uses an existing vulnerability in Universal Plug and Play (UPnP) protocol to get past network security and flood

2919-463: A low-level attack and a warning that a larger attack will be carried out if a ransom is not paid in bitcoin . Security experts recommend targeted websites to not pay the ransom. The attackers tend to get into an extended extortion scheme once they recognize that the target is ready to pay. First discovered in 2009, the HTTP slow POST attack sends a complete, legitimate HTTP POST header , which includes

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3058-532: A message) through garlic routing , and even the end points ("destinations") are cryptographic identifiers (essentially a pair of public keys ), so that neither senders nor recipients of messages need to reveal their IP address to the other side or to third-party observers. Although many developers had been a part of the Invisible IRC Project (IIP) and Freenet communities, significant differences exist between their designs and concepts. IIP

3197-426: A mode in which it connects only to friends, and an opennet-mode in which it connects to any other Freenet user. Both modes can be run simultaneously. When a user switches to pure darknet operation, Freenet becomes very difficult to detect from the outside. The transport layer created for the darknet mode allows communication over restricted routes as commonly found in mesh networks , as long as these connections follow

3336-399: A neighbor to any other; no hierarchy or other structure is intended. Each message is routed through the network by passing from neighbor to neighbor until it reaches its destination. As each node passes a message to a neighbor, it does not know whether the neighbor will forward the message to another node, or is the final destination or original source of the message. This is intended to protect

3475-454: A piece of malware that targeted IoT devices, used PDoS attacks to disable its targets. PhlashDance is a tool created by Rich Smith (an employee of Hewlett-Packard 's Systems Security Lab) used to detect and demonstrate PDoS vulnerabilities at the 2008 EUSecWest Applied Security Conference in London, UK. A distributed denial-of-service attack may involve sending forged requests of some type to

3614-467: A record-breaking packet DDoS at 3.15 billion packets per second, which targeted an undisclosed number of unofficial Minecraft game servers . In October 2024, the Internet Archive faced two severe DDoS attacks that brought the site completely offline, immediately following a previous attack that leaked records of over 31 million of the site's users. The hacktivist group SN_Blackmeta claimed

3753-517: A second file with the same name can cause collisions. USKs resolve this by adding a version number to the keys which is also used for providing update notification for keys registered as bookmarks in the web interface. Another subtype of the SSK is the Keyword Signed Key, or KSK, in which the key pair is generated in a standard way from a simple human-readable string. Inserting a document using

3892-532: A seized machine which had been running I2P router software may hold unencrypted local data that could be useful to law enforcement . Records of which websites a user of a later-seized machine was interested in may also be inferred. The study identified a "trusted" I2P domain registrar ("NO.i2p") which appeared to have been abandoned by its administrator, and which the study identified as a potential target for law enforcement takeover. It alternatively suggested waiting for NO.i2p's server to fail, only to social engineer

4031-430: A server with millions of requests to slow its performance, overwhelming a server with a substantial amount of invalid data, to submitting requests with an illegitimate IP address . In a distributed denial-of-service attack ( DDoS attack ), the incoming traffic flooding the victim originates from many different sources. More sophisticated strategies are required to mitigate this type of attack; simply attempting to block

4170-414: A single hybrid node. Unlike many other P2P applications Freenet does not provide comprehensive functionality itself. Freenet is modular and features an API called Freenet Client Protocol (FCP) for other programs to use to implement services such as message boards , file sharing, or online chat . Freenet Messaging System (FMS) Frost Sone Denial-of-service attack In computing ,

4309-479: A single machine and are harder to disable, and the behavior of each attack machine can be stealthier, making the attack harder to track and shut down. Since the incoming traffic flooding the victim originates from different sources, it may be impossible to stop the attack simply by using ingress filtering . It also makes it difficult to distinguish legitimate user traffic from attack traffic when spread across multiple points of origin. As an alternative or augmentation of

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4448-510: A single source is insufficient as there are multiple sources. A DoS or DDoS attack is analogous to a group of people crowding the entry door of a shop, making it hard for legitimate customers to enter, thus disrupting trade and losing the business money. Criminal perpetrators of DoS attacks often target sites or services hosted on high-profile web servers such as banks or credit card payment gateways . Revenge and blackmail , as well as hacktivism , can motivate these attacks. Panix ,

4587-444: A small-world network (which includes both opennet and darknet style Freenet networks), when ignoring the caching which could improve the scalability for popular content. However, this scalability is difficult to test without a very large network. Furthermore, the security features inherent to Freenet make detailed performance analysis (including things as simple as determining the size of the network) difficult to do accurately. As of now,

4726-416: A specific machine. The attacker will send large numbers of IP packets with the source address faked to appear to be the address of the victim. Most devices on a network will, by default, respond to this by sending a reply to the source IP address. If the number of machines on the network that receive and respond to these packets is very large, the victim's computer will be flooded with traffic. This overloads

4865-430: A system crash on a vulnerable system. The BlackNurse attack is an example of an attack taking advantage of the required Destination Port Unreachable ICMP packets. A nuke is an old-fashioned denial-of-service attack against computer networks consisting of fragmented or otherwise invalid ICMP packets sent to the target, achieved by using a modified ping utility to repeatedly send this corrupt data , thus slowing down

5004-476: A target's network and servers. The attack is based on a DNS amplification technique, but the attack mechanism is a UPnP router that forwards requests from one outer source to another. The UPnP router returns the data on an unexpected UDP port from a bogus IP address, making it harder to take simple action to shut down the traffic flood. According to the Imperva researchers, the most effective way to stop this attack

5143-432: A tool to test the security of servers against this type of attack. A Challenge Collapsar (CC) attack is an attack where standard HTTP requests are sent to a targeted web server frequently. The Uniform Resource Identifiers (URIs) in the requests require complicated time-consuming algorithms or database operations which may exhaust the resources of the targeted web server. In 2004, a Chinese hacker nicknamed KiKi invented

5282-438: A very large number of computers that will reply to the requests. Using Internet Protocol address spoofing , the source address is set to that of the targeted victim, which means all the replies will go to (and flood) the target. This reflected attack form is sometimes called a distributed reflective denial-of-service ( DRDoS ) attack. ICMP echo request attacks ( Smurf attacks ) can be considered one form of reflected attack, as

5421-400: A very long time. The attacker establishes hundreds or even thousands of such connections until all resources for incoming connections on the victim server are exhausted, making any further connections impossible until all data has been sent. It is notable that unlike many other DDoS or DDoS attacks, which try to subdue the server by overloading its network or CPU, an HTTP slow POST attack targets

5560-597: A wide range of source IP addresses, giving the appearance of a distributed DoS. These flood attacks do not require completion of the TCP three-way handshake and attempt to exhaust the destination SYN queue or the server bandwidth. Because the source IP addresses can be trivially spoofed, an attack could come from a limited set of sources, or may even originate from a single host. Stack enhancements such as SYN cookies may be effective mitigation against SYN queue flooding but do not address bandwidth exhaustion. In 2022, TCP attacks were

5699-485: A wide variety of DDoS tools are available today, including paid and free versions, with different features available. There is an underground market for these in hacker-related forums and IRC channels. Application-layer attacks employ DoS-causing exploits and can cause server-running software to fill the disk space or consume all available memory or CPU time . Attacks may use specific packet types or connection requests to saturate finite resources by, for example, occupying

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5838-475: Is a peer-to-peer platform for censorship -resistant, anonymous communication. It uses a decentralized distributed data store to keep and deliver information, and has a suite of free software for publishing and communicating on the Web without fear of censorship. Both Freenet and some of its associated tools were originally designed by Ian Clarke , who defined Freenet's goal as providing freedom of speech on

5977-566: Is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers . The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO). The model groups similar communication functions into one of seven logical layers. A layer serves the layer above it and

6116-515: Is a denial-of-service attack on the Transmission Control Protocol where the attacker employs man-in-the-middle techniques . It exploits a weakness in TCP's re-transmission timeout mechanism, using short synchronized bursts of traffic to disrupt TCP connections on the same link. A slow read attack sends legitimate application layer requests, but reads responses very slowly, keeping connections open longer hoping to exhaust

6255-1047: Is a form of DDoS attack where attackers target application-layer processes. The attack over-exercises specific functions or features of a website with the intention to disable those functions or features. This application-layer attack is different from an entire network attack, and is often used against financial institutions to distract IT and security personnel from security breaches. In 2013, application-layer DDoS attacks represented 20% of all DDoS attacks. According to research by Akamai Technologies , there have been "51 percent more application layer attacks" from Q4 2013 to Q4 2014 and "16 percent more" from Q3 2014 to Q4 2014. In November 2017; Junade Ali, an engineer at Cloudflare noted that whilst network-level attacks continue to be of high capacity, they were occurring less frequently. Ali further noted that although network-level attacks were becoming less frequent, data from Cloudflare demonstrated that application-layer attacks were still showing no sign of slowing down. The OSI model (ISO/IEC 7498-1)

6394-424: Is controlled through the router console, which is a web frontend accessed through a web browser. Currently, Vuze and BiglyBT are the torrent clients that make clearnet (connections not through I2P) torrents available on I2P and vice versa. Depending on the client settings, torrents from the internet can be made available on I2P (via announcements to I2P's DHT network) and torrents from I2P can be made available to

6533-503: Is essentially random. In opennet connections are established by a join request which provides an optimized network structure if the existing network is already optimized. So the data in a newly started Freenet will be distributed somewhat randomly. As location swapping (on darknet) and path folding (on opennet) progress, nodes which are close to one another will increasingly have close locations, and nodes which are far away will have distant locations. Data with similar keys will be stored on

6672-516: Is for companies to lock down UPnP routers. In 2014, it was discovered that Simple Service Discovery Protocol (SSDP) was being used in DDoS attacks known as an SSDP reflection attac k with amplification . Many devices, including some residential routers, have a vulnerability in the UPnP software that allows an attacker to get replies from UDP port 1900 to a destination address of their choice. With

6811-402: Is handled like a connection request, causing the server to spawn a half-open connection , send back a TCP/SYN-ACK packet, and wait for a packet in response from the sender address. However, because the sender's address is forged, the response never comes. These half-open connections exhaust the available connections the server can make, keeping it from responding to legitimate requests until after

6950-416: Is made possible by the fact that human relationships tend to form small-world networks, a property that can be exploited to find short paths between any two people. The work is based on a speech given at DEF CON 13 by Ian Clarke and Swedish mathematician Oskar Sandberg . Furthermore, the routing algorithm is capable of routing over a mixture of opennet and darknet connections, allowing people who have only

7089-480: Is no botnet and the attacker does not have to communicate with the clients it subverts. Instead, the attacker acts as a puppet master , instructing clients of large peer-to-peer file sharing hubs to disconnect from their peer-to-peer network and to connect to the victim's website instead. Permanent denial-of-service (PDoS), also known loosely as phlashing, is an attack that damages a system so badly that it requires replacement or reinstallation of hardware. Unlike

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7228-552: Is no notion of semantic closeness when speaking of key closeness. Therefore, there will be no correlation between key closeness and similar popularity of data as there might be if keys did exhibit some semantic meaning, thus avoiding bottlenecks caused by popular subjects. There are two main varieties of keys in use on Freenet, the Content Hash Key (CHK) and the Signed Subspace Key (SSK). A subtype of SSKs

7367-444: Is not retrieved regularly (see also Effect ). While users can insert data into the network, there is no way to delete data. Due to Freenet's anonymous nature the original publishing node or owner of any piece of data is unknown. The only way data can be removed is if users don't request it. Typically, a host computer on the network runs the software that acts as a node, and it connects to other hosts running that same software to form

7506-407: Is not subject to the control of any one individual or organization, including the designers of Freenet. The codebase size is over 192,000 lines of code . Information stored on Freenet is distributed around the network and stored on several different nodes. Encryption of data and relaying of requests makes it difficult to determine who inserted content into Freenet, who requested that content, or where

7645-473: Is served by the layer below it. For example, a layer that provides error-free communications across a network provides the communications path needed by applications above it, while it calls the next lower layer to send and receive packets that traverse that path. In the OSI model, the definition of its application layer is narrower in scope than is often implemented. The OSI model defines the application layer as being

7784-502: Is the Updatable Subspace Key (USK) which adds versioning to allow secure updating of content. A CHK is a SHA-256 hash of a document (after encryption, which itself depends on the hash of the plaintext) and thus a node can check that the document returned is correct by hashing it and checking the digest against the key. This key contains the meat of the data on Freenet. It carries all the binary data building blocks for

7923-457: Is to brick the device, rendering it unusable for its original purpose until it can be repaired or replaced. The PDoS is a pure hardware-targeted attack that can be much faster and requires fewer resources than using a botnet in a DDoS attack. Because of these features, and the potential and high probability of security exploits on network-enabled embedded devices, this technique has come to the attention of numerous hacking communities. BrickerBot ,

8062-589: Is typically several GB (or more). Files on Freenet are typically split into multiple small blocks, with duplicate blocks created to provide redundancy . Each block is handled independently, meaning that a single file may have parts stored on many different nodes. Information flow in Freenet is different from networks like eMule or BitTorrent ; in Freenet: Two advantages of this design are high reliability and anonymity. Information remains available even if

8201-499: Is unlikely to meet the $ 30,000 Bitcoin ransom. In August 2023, the group of hacktivists NoName057 targeted several Italian financial institutions, through the execution of slow DoS attacks . On 14 January 2024, they executed a DDoS attack on Swiss federal websites, prompted by President Zelensky 's attendance at the Davos World Economic Forum . Switzerland's National Cyber Security Centre quickly mitigated

8340-438: Is used, so that seldom-used data will tend to be on just a few nodes which specialize in providing that data, and frequently used items will be spread widely throughout the network. This automatic mirroring counteracts the times when web traffic becomes overloaded, and due to a mature network's intelligent routing, a network of size n should require only log( n ) time to retrieve a document on average. Keys are hashes : there

8479-402: The 2002 New Hampshire Senate election phone jamming scandal , telemarketers were used to flood political opponents with spurious calls to jam phone banks on election day. Widespread publication of a number can also flood it with enough calls to render it unusable, as happened by accident in 1981 with multiple +1- area code -867-5309 subscribers inundated by hundreds of calls daily in response to

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8618-520: The Las Vegas Strip for over an hour. The release of sample code during the event led to the online attack of Sprint , EarthLink , E-Trade , and other major corporations in the year to follow. The largest DDoS attack to date happened in September 2017, when Google Cloud experienced an attack with a peak volume of 2.54 Tb/s , revealed by Google on October 17, 2020. The record holder

8757-500: The University of Edinburgh , which he completed as a graduation requirement in the summer of 1999. Ian Clarke's resulting unpublished report "A distributed decentralized information storage and retrieval system" (1999) provided foundation for the seminal paper written in collaboration with other researchers, "Freenet: A Distributed Anonymous Information Storage and Retrieval System" (2001). According to CiteSeer , it became one of

8896-446: The bandwidth or resources of a targeted system, usually one or more web servers. A DDoS attack uses more than one unique IP address or machines, often from thousands of hosts infected with malware . A distributed denial of service attack typically involves more than around 3–5 nodes on different networks; fewer nodes may qualify as a DoS attack but is not a DDoS attack. Multiple attack machines can generate more attack traffic than

9035-562: The logical resources of the victim, which means the victim would still have enough network bandwidth and processing power to operate. Combined with the fact that the Apache HTTP Server will, by default, accept requests up to 2GB in size, this attack can be particularly powerful. HTTP slow POST attacks are difficult to differentiate from legitimate connections and are therefore able to bypass some protection systems. OWASP , an open source web application security project, released

9174-557: The Chinese authorities on the mainland. It was reported that in 2002 Freenet China had several thousand dedicated users. However, Freenet opennet traffic was blocked in China around the 2010s. The Freenet file sharing network stores documents and allows them to be retrieved later by an associated key, as is now possible with protocols such as HTTP . The network is designed to be highly survivable. The system has no central servers and

9313-816: The DDoS attack as retribution for American involvement in the Israel–Hamas war , despite the Internet Archive being unaffiliated with the United States government; however, their link with the preceding data leak remains unclear. Denial-of-service attacks are characterized by an explicit attempt by attackers to prevent legitimate use of a service. There are two general forms of DoS attacks: those that crash services and those that flood services. The most serious attacks are distributed. A distributed denial-of-service (DDoS) attack occurs when multiple systems flood

9452-486: The Freenet core stopped using the db4o database and laid the foundation for an efficient interface to the Web of Trust plugin which provides spam resistance. Freenet has always been free software, but until 2011 it required users to install Java . This problem was solved by making Freenet compatible with OpenJDK , a free and open source implementation of the Java Platform. On 11 February 2015, Freenet received

9591-443: The Freenet network. In this way, it is more similar to Tor's onion services than to anonymous proxy software like Tor's proxy . Freenet's focus lies on free speech and anonymity. Because of that, Freenet acts differently at certain points that are (directly or indirectly) related to the anonymity part. Freenet attempts to protect the anonymity of both people inserting data into the network (uploading) and those retrieving data from

9730-415: The Freenet network. The simplest is via FProxy, which is integrated with the node software and provides a web interface to content on the network. Using FProxy, a user can browse freesites (websites that use normal HTML and related tools, but whose content is stored within Freenet rather than on a traditional web server). The web interface is also used for most configuration and node management tasks. Through

9869-575: The I2P community into moving to a phony replacement. Another suggestion the study proposed was to register a mirror version of a target website under an identical domain. From August 15, 2015 to August 16, 2015 an I2P convention was held in Toronto, Ontario . The conference was hosted by a local hackerspace , Hacklab. The conference featured presentations from I2P developers and security researchers. Freenet Hyphanet (until mid-2023: Freenet )

10008-442: The Internet with strong anonymity protection. The distributed data store of Freenet is used by many third-party programs and plugins to provide microblogging and media sharing, anonymous and decentralised version tracking, blogging, a generic web of trust for decentralized spam resistance , Shoeshop for using Freenet over sneakernet , and many more. The origin of Freenet can be traced to Ian Clarke's student project at

10147-469: The NTP is through a command called monlist, which sends the details of the last 600 hosts that have requested the time from the NTP server back to the requester. A small request to this time server can be sent using a spoofed source IP address of some victim, which results in a response 556.9 times the size of the request being sent to the victim. This becomes amplified when using botnets that all send requests with

10286-540: The SUMA-Award for "protection against total surveillance". Freenet served as the model for the Japanese peer to peer file-sharing programs Winny , Share and Perfect Dark , but this model differs from p2p networks such as Bittorrent and emule . Freenet separates the underlying network structure and protocol from how users interact with the network; as a result, there are a variety of ways to access content on

10425-555: The UK, the US, and Germany. Particularly, the UK's financial sector saw an increase in DDoS attacks from nation-state actors and hacktivists, aimed at undermining Ukraine's allies. In February 2023, Cloudflare faced a 71 million/requests per second attack which Cloudflare claims was the largest HTTP DDoS attack at the time. HTTP DDoS attacks are measured by HTTP requests per second instead of packets per second or bits per second. On July 10, 2023,

10564-724: The affected computer until it comes to a complete stop. A specific example of a nuke attack that gained some prominence is the WinNuke , which exploited the vulnerability in the NetBIOS handler in Windows 95 . A string of out-of-band data was sent to TCP port 139 of the victim's machine, causing it to lock up and display a Blue Screen of Death . Attackers have found a way to exploit a number of bugs in peer-to-peer servers to initiate DDoS attacks. The most aggressive of these peer-to-peer-DDoS attacks exploits DC++ . With peer-to-peer there

10703-411: The anonymity of users and publishers. Each node maintains a data store containing documents associated with keys, and a routing table associating nodes with records of their performance in retrieving different keys. The Freenet protocol uses a key-based routing protocol, similar to distributed hash tables . The routing algorithm changed significantly in version 0.7. Prior to version 0.7, Freenet used

10842-518: The application layer can disrupt services such as the retrieval of information or search functions on a website. An advanced persistent DoS (APDoS) is associated with an advanced persistent threat and requires specialized DDoS mitigation . These attacks can persist for weeks; the longest continuous period noted so far lasted 38 days. This attack involved approximately 50+ petabits (50,000+ terabits) of malicious traffic. Attackers in this scenario may tactically switch between several targets to create

10981-423: The attack ends. A teardrop attack involves sending mangled IP fragments with overlapping, oversized payloads to the target machine. This can crash various operating systems because of a bug in their TCP/IP fragmentation re-assembly code. Windows 3.1x , Windows 95 and Windows NT operating systems, as well as versions of Linux prior to versions 2.0.32 and 2.1.63 are vulnerable to this attack. One of

11120-535: The attack, ensuring core federal services remained secure, despite temporary accessibility issues on some websites. In October 2023, exploitation of a new vulnerability in the HTTP/2 protocol resulted in the record for largest HTTP DDoS attack being broken twice, once with a 201 million requests per second attack observed by Cloudflare, and again with a 398 million requests per second attack observed by Google . In August 2024, Global Secure Layer observed and reported on

11259-411: The attacker disrupts control packets using a hidden Markov model . A setting in which Markov-model based attacks are prevalent is online gaming as the disruption of the control packet undermines game play and system functionality. The United States Computer Emergency Readiness Team (US-CERT) has identified symptoms of a denial-of-service attack to include: In cases such as MyDoom and Slowloris ,

11398-440: The attacker sends traffic consisting of complicated requests to the system. Essentially, a sophisticated DDoS attack is lower in cost due to its use of less traffic, is smaller in size making it more difficult to identify, and it has the ability to hurt systems which are protected by flow control mechanisms. A SYN flood occurs when a host sends a flood of TCP/SYN packets, often with a forged sender address. Each of these packets

11537-482: The attacker uses a client program to connect to handlers, which are compromised systems that issue commands to the zombie agents, which in turn facilitate the DDoS attack. Agents are compromised via the handlers by the attacker. Each handler can control up to a thousand agents. In some cases a machine may become part of a DDoS attack with the owner's consent, for example, in Operation Payback , organized by

11676-452: The attacker using automated routines to exploit vulnerabilities in programs that accept remote connections running on the targeted remote hosts. Each handler can control up to a thousand agents. In other cases a machine may become part of a DDoS attack with the owner's consent, for example, in Operation Payback organized by the group Anonymous . The Low Orbit Ion Cannon has typically been used in this way. Along with High Orbit Ion Cannon

11815-592: The availability of well known websites to legitimate users. More sophisticated attackers use DDoS tools for the purposes of extortion  – including against their business rivals. It has been reported that there are new attacks from internet of things (IoT) devices that have been involved in denial of service attacks. In one noted attack that was made peaked at around 20,000 requests per second which came from around 900 CCTV cameras. UK's GCHQ has tools built for DDoS, named PREDATORS FACE and ROLLING THUNDER. Simple attacks such as SYN floods may appear with

11954-586: The beneficial uses of Freenet outweigh its negative uses. Their view is that free speech, in itself, is not in contradiction with any other consideration—the information is not the crime. Freenet attempts to remove the possibility of any group imposing its beliefs or values on any data. Although many states censor communications to different extents, they all share one commonality in that a body must decide what information to censor and what information to allow. What may be acceptable to one group of people may be considered offensive or even dangerous to another. In essence,

12093-541: The client, preventing outside access, as well as flooding the client with the sent packets. A LAND attack is of this type. Pulsing zombies are compromised computers that are directed to launch intermittent and short-lived floodings of victim websites with the intent of merely slowing it rather than crashing it. This type of attack, referred to as degradation-of-service , can be more difficult to detect and can disrupt and hamper connection to websites for prolonged periods of time, potentially causing more overall disruption than

12232-401: The content to be delivered to the client for reassembly and decryption. The CHK is unique by nature and provides tamperproof content. A hostile node altering the data under a CHK will immediately be detected by the next node or the client. CHKs also reduce the redundancy of data since the same data will have the same CHK and when multiple sites reference the same large files, they can reference to

12371-458: The content was stored. This protects the anonymity of participants, and also makes it very difficult to censor specific content. Content is stored encrypted, making it difficult for even the operator of a node to determine what is stored on that node. This provides plausible deniability ; which, in combination with request relaying, means that safe harbor laws that protect service providers may also protect Freenet node operators. When asked about

12510-735: The darknet (a subset of the global social network) is a small-world network, and nodes constantly attempt to swap locations (using the Metropolis–Hastings algorithm ) in order to minimize their distance to their neighbors. If the network actually is a small-world network, Freenet should find data reasonably quickly; ideally on the order of O ( [ l o g ( n ) ] 2 ) {\displaystyle O\left(\left[log\left(n\right)\right]^{2}\right)} hops in Big O notation . However, it does not guarantee that data will be found at all. Eventually, either

12649-402: The development of version 0.7) shows that this "path folding" is critical, and that a very simple routing algorithm will suffice provided there is path folding. The disadvantage of this is that it is very easy for an attacker to find Freenet nodes, and connect to them, because every node is continually attempting to find new connections. In version 0.7, Freenet supports both "opennet" (similar to

12788-562: The device becomes infected. The IoT device itself is not the direct target of the attack, it is used as a part of a larger attack. Once the hacker has enslaved the desired number of devices, they instruct the devices to try to contact an ISP. In October 2016, a Mirai botnet attacked Dyn which is the ISP for sites such as Twitter , Netflix , etc. As soon as this occurred, these websites were all unreachable for several hours. RUDY attack targets web applications by starvation of available sessions on

12927-432: The distributed denial-of-service attack, a PDoS attack exploits security flaws which allow remote administration on the management interfaces of the victim's hardware, such as routers , printers, or other networking hardware . The attacker uses these vulnerabilities to replace a device's firmware with a modified, corrupt, or defective firmware image—a process which when done legitimately is known as flashing. The intent

13066-481: The document is found or the hop limit is exceeded. The terminal node sends a reply that makes its way back to the originator along the route specified by the intermediate nodes' records of pending requests. The intermediate nodes may choose to cache the document along the way. Besides saving bandwidth, this also makes documents harder to censor as there is no one "source node". Initially, the locations in darknet are distributed randomly. This means that routing of requests

13205-425: The fanfiction platform Archive of Our Own (AO3) faced DDoS attacks, disrupting services. Anonymous Sudan , claiming the attack for religious and political reasons, was viewed skeptically by AO3 and experts. Flashpoint, a threat intelligence vendor, noted the group's past activities but doubted their stated motives. AO3, supported by the non-profit Organization for Transformative Works (OTW) and reliant on donations,

13344-407: The fields in an IP header is the fragment offset field, indicating the starting position, or offset, of the data contained in a fragmented packet relative to the data in the original packet. If the sum of the offset and size of one fragmented packet differs from that of the next fragmented packet, the packets overlap. When this happens, a server vulnerable to teardrop attacks is unable to reassemble

13483-513: The financial or legal infrastructure to support a network of exit nodes ". The reseed servers, a sort of bootstrap nodes, which connect the user with the initial set of peers to join the I2P-network, should be run by volunteers. Since I2P is an anonymizing network layer , it is designed so other software can use it for anonymous communication. As such, there are a variety of tools currently available for I2P or in development. The I2P router

13622-574: The flooding hosts send Echo Requests to the broadcast addresses of mis-configured networks, thereby enticing hosts to send Echo Reply packets to the victim. Some early DDoS programs implemented a distributed form of this attack. Amplification attacks are used to magnify the bandwidth that is sent to a victim. Many services can be exploited to act as reflectors, some harder to block than others. US-CERT have observed that different services may result in different amplification factors, as tabulated below: DNS amplification attacks involves an attacker sending

13761-597: The group Anonymous . These attacks can use different types of internet packets such as TCP, UDP, ICMP, etc. These collections of compromised systems are known as botnets . DDoS tools like Stacheldraht still use classic DoS attack methods centered on IP spoofing and amplification like smurf attacks and fraggle attacks (types of bandwidth consumption attacks). SYN floods (a resource starvation attack) may also be used. Newer tools can use DNS servers for DoS purposes. Unlike MyDoom's DDoS mechanism, botnets can be turned against any IP address. Script kiddies use them to deny

13900-480: The internet. For this reason, torrents previously published only on I2P can be made available to the entire Internet, and users of I2P can often download popular content from the Internet while maintaining the anonymity of I2P. As of August 2022, the default outproxy is exit.stormycloud.i2p which is run by StormyCloud Inc. The Privacy Solutions project, a new organization that develops and maintains I2P software, launched several new development efforts designed to enhance

14039-462: The key's hash is turned into another number in the same range, and the request is routed to the node whose location is closest to the key. This goes on until some number of hops is exceeded, there are no more nodes to search, or the data is found. If the data is found, it is cached on each node along the path. So there is no one source node for a key, and attempting to find where it is currently stored will result in it being cached more widely. Essentially

14178-407: The leading method in DDoS incidents, accounting for 63% of all DDoS activity. This includes tactics like TCP SYN , TCP ACK, and TCP floods. With TCP being the most widespread networking protocol, its attacks are expected to remain prevalent in the DDoS threat scene. In 2015, DDoS botnets such as DD4BC grew in prominence, taking aim at financial institutions. Cyber-extortionists typically begin with

14317-545: The maximum number of open connections or filling the victim's disk space with logs. An attacker with shell-level access to a victim's computer may slow it until it is unusable or crash it by using a fork bomb . Another kind of application-level DoS attack is XDoS (or XML DoS) which can be controlled by modern web application firewalls (WAFs). All attacks belonging to the category of timeout exploiting . Slow DoS attacks implement an application-layer attack. Examples of threats are Slowloris, establishing pending connections with

14456-501: The most frequently cited computer science articles in 2002. Freenet can provide anonymity on the Internet by storing small encrypted snippets of content distributed on the computers of its users and connecting only through intermediate computers which pass on requests for content and sending them back without knowing the contents of the full file. This is similar to how routers on the Internet route packets without knowing anything about files ‍ — except Freenet has caching,

14595-482: The network (downloading). Unlike file sharing systems, there is no need for the uploader to remain on the network after uploading a file or group of files. Instead, during the upload process, the files are broken into chunks and stored on a variety of other computers on the network. When downloading, those chunks are found and reassembled. Every node on the Freenet network contributes storage space to hold files and bandwidth that it uses to route requests from its peers. As

14734-425: The network, and can make it difficult for an attacker (such as an oppressive government) to even determine that a user is running Freenet in the first place. The core innovation in Freenet 0.7 is to allow a globally scalable darknet, capable (at least in theory) of supporting millions of users. Previous darknets, such as WASTE , have been limited to relatively small disconnected networks. The scalability of Freenet

14873-473: The network, though a site operator may secure their site against certain versions of this type of attack to some extent. A zero-day vulnerability was discovered for I2P in 2014, and was exploited to de-anonymize at least 30,000 users. This included users of the operating system Tails . This vulnerability was later patched. A 2017 study examining how forensic investigators might exploit vulnerabilities in I2P software to gather useful evidence indicated that

15012-431: The old algorithms, but simpler), and "darknet" (all node connections are set up manually, so only your friends know your node's IP address). Darknet is less convenient, but much more secure against a distant attacker. This change required major changes in the routing algorithm. Every node has a location, which is a number between 0 and 1. When a key is requested, first the node checks the local data store. If it's not found,

15151-425: The other hand, if an attacker uses many systems to simultaneously launch attacks against a remote host, this would be classified as a DDoS attack. Malware can carry DDoS attack mechanisms; one of the better-known examples of this was MyDoom . Its DoS mechanism was triggered on a specific date and time. This type of DDoS involved hardcoding the target IP address before releasing the malware and no further interaction

15290-526: The packets resulting in a denial-of-service condition. Voice over IP has made abusive origination of large numbers of telephone voice calls inexpensive and easily automated while permitting call origins to be misrepresented through caller ID spoofing . According to the US Federal Bureau of Investigation , telephony denial-of-service (TDoS) has appeared as part of various fraudulent schemes: TDoS can exist even without Internet telephony . In

15429-440: The previous main developer, jrandom , is currently on hiatus, others, such as zzz , killyourtv , and Complication have continued to lead development efforts, and are assisted by numerous contributors. I2P uses 2048bit ElGamal / AES256 / SHA256 +Session Tags encryption and Ed25519 EdDSA / ECDSA signatures . I2P has had a stable release every six to eight weeks. Updates are distributed via I2P torrents and are signed by

15568-428: The privacy, security, and anonymity for users, based on I2P protocols and technology. These efforts include: The code repository and download sections for the i2pd and Abscond project is available for the public to review and download. Effective January, 2015 i2pd is operating under PurpleI2P. Some cryptocurrencies that support I2P are listed below. Denial of service attacks are possible against websites hosted on

15707-414: The provider to meet the defined QoS levels for the increased requests. The main incentive behind such attacks may be to drive the application owner to raise the elasticity levels to handle the increased application traffic, to cause financial losses, or force them to become less competitive. A banana attack is another particular type of DoS. It involves redirecting outgoing messages from the client back onto

15846-438: The publisher node goes offline, and is anonymously spread over many hosting nodes as encrypted blocks, not entire files. The key disadvantage of the storage method is that no one node is responsible for any chunk of data. If a piece of data is not retrieved for some time and a node keeps getting new data, it will drop the old data sometime when its allocated disk space is fully used. In this way Freenet tends to 'forget' data which

15985-411: The purpose of Freenet is to ensure that no one is allowed to decide what is acceptable. Reports of Freenet's use in authoritarian nations is difficult to track due to the very nature of Freenet's goals. One group, Freenet China , used to introduce the Freenet software to Chinese users starting from 2001 and distribute it within China through e-mails and on disks after the group's website was blocked by

16124-511: The release manager (generally zzz or str4d ). The website states that "funding for I2P comes entirely from donations". Admins and managers of the project said that "the core project itself doesn't take donations". These should instead go to secondary applications or be spent on hiring others, to work on I2P. Support for the onboarding for I2P came from the Open Technology Fund . In contrast to The Tor Project , I2P has "not

16263-532: The same CHK. SSKs are based on public-key cryptography. Currently Freenet uses the DSA algorithm. Documents inserted under SSKs are signed by the inserter, and this signature can be verified by every node to ensure that the data is not tampered with. SSKs can be used to establish a verifiable pseudonymous identity on Freenet, and allow for multiple documents to be inserted securely by a single person. Files inserted with an SSK are effectively immutable , since inserting

16402-445: The same node. The result is that the network will self-organize into a distributed, clustered structure where nodes tend to hold data items that are close together in key space. There will probably be multiple such clusters throughout the network, any given document being replicated numerous times, depending on how much it is used. This is a kind of " spontaneous symmetry breaking ", in which an initially symmetric state (all nodes being

16541-417: The same process is used to insert a document into the network: the data is routed according to the key until it runs out of hops, and if no existing document is found with the same key, it is stored on each node. If older data is found, the older data is propagated and returned to the originator, and the insert "collides". But this works only if the locations are clustered in the right way. Freenet assumes that

16680-403: The same spoofed IP source, which will result in a massive amount of data being sent back to the victim. It is very difficult to defend against these types of attacks because the response data is coming from legitimate servers. These attack requests are also sent through UDP, which does not require a connection to the server. This means that the source IP is not verified when a request is received by

16819-408: The same, with random initial keys for each other) leads to a highly asymmetric situation, with nodes coming to specialize in data that has closely related keys. There are forces which tend to cause clustering (shared closeness data spreads throughout the network), and forces that tend to break up clusters (local caching of commonly used data). These forces will be different depending on how often data

16958-485: The scalability of Freenet has yet to be tested. As of version 0.7, Freenet supports both "darknet" and "opennet" connections. Opennet connections are made automatically by nodes with opennet enabled, while darknet connections are manually established between users that know and trust each other. Freenet developers describe the trust needed as "will not crack their Freenet node". Opennet connections are easy to use, but darknet connections are more secure against attackers on

17097-478: The server's connection pool. The slow read is achieved by advertising a very small number for the TCP Receive Window size, and at the same time emptying clients' TCP receive buffer slowly, which causes a very low data flow rate. A sophisticated low-bandwidth DDoS attack is a form of DoS that uses less traffic and increases its effectiveness by aiming at a weak point in the victim's system design, i.e.,

17236-583: The server. To bring awareness of these vulnerabilities, campaigns have been started that are dedicated to finding amplification vectors which have led to people fixing their resolvers or having the resolvers shut down completely. The Mirai botnet works by using a computer worm to infect hundreds of thousands of IoT devices across the internet. The worm propagates through networks and systems taking control of poorly protected IoT devices such as thermostats, Wi-Fi-enabled clocks, and washing machines. The owner or user will usually have no immediate indication of when

17375-418: The song " 867-5309/Jenny ". TDoS differs from other telephone harassment (such as prank calls and obscene phone calls ) by the number of calls originated. By occupying lines continuously with repeated automated calls, the victim is prevented from making or receiving both routine and emergency telephone calls. Related exploits include SMS flooding attacks and black fax or continuous fax transmission by using

17514-590: The target's system resources. Bandwidth-saturating floods rely on the attacker's ability to generate the overwhelming flux of packets. A common way of achieving this today is via distributed denial-of-service, employing a botnet . An application layer DDoS attack is done mainly for specific targeted purposes, including disrupting transactions and access to databases. It requires fewer resources than network layer attacks but often accompanies them. An attack may be disguised to look like legitimate traffic, except it targets specific application packets or functions. The attack on

17653-469: The third-oldest ISP in the world, was the target of what is thought to be the first DoS attack. On September 6, 1996, Panix was subject to a SYN flood attack, which brought down its services for several days while hardware vendors, notably Cisco , figured out a proper defense. Another early demonstration of the DoS attack was made by Khan C. Smith in 1997 during a DEF CON event, disrupting Internet access to

17792-407: The tools are embedded in malware and launch their attacks without the knowledge of the system owner. Stacheldraht is a classic example of a DDoS tool. It uses a layered structure where the attacker uses a client program to connect to handlers which are compromised systems that issue commands to the zombie agents which in turn facilitate the DDoS attack. Agents are compromised via the handlers by

17931-454: The topic, Freenet developers defer to the EFF discussion which says that not being able to filter anything is a safe choice. Like Winny , Share and Perfect Dark , Freenet not only transmits data between nodes but actually stores them, working as a huge distributed cache. To achieve this, each node allocates some amount of disk space to store data; this is configurable by the node operator, but

18070-508: The use of separate applications or plugins loaded into the node software, users can interact with the network in other ways, such as forums similar to web forums or Usenet or interfaces more similar to traditional P2P "filesharing" interfaces. While Freenet provides an HTTP interface for browsing freesites, it is not a proxy for the World Wide Web ; Freenet can be used to access only the content that has been previously inserted into

18209-448: The user interface. The OSI application layer is responsible for displaying data and images to the user in a human-recognizable format and to interface with the presentation layer below it. In an implementation, the application and presentation layers are frequently combined. The simplest DoS attack relies primarily on brute force, flooding the target with an overwhelming flux of packets, oversaturating its connection bandwidth or depleting

18348-499: The victim scales back down, the attack resumes, causing resources to scale back up again. This can result in a reduced quality of service during the periods of scaling up and down and a financial drain on resources during periods of over-provisioning while operating with a lower cost for an attacker compared to a normal DDoS attack, as it only needs to be generating traffic for a portion of the attack period. An application layer DDoS attack (sometimes referred to as layer 7 DDoS attack )

18487-418: The victim's computer and can even make it unusable during such an attack. Ping flood is based on sending the victim an overwhelming number of ping packets, usually using the ping command from Unix-like hosts. It is very simple to launch, the primary requirement being access to greater bandwidth than the victim. Ping of death is based on sending the victim a malformed ping packet, which will lead to

18626-482: The victim, or SlowDroid , an attack running on mobile devices. Another target of DDoS attacks may be to produce added costs for the application operator, when the latter uses resources based on cloud computing . In this case, normally application-used resources are tied to a needed quality of service (QoS) level (e.g. responses should be less than 200 ms) and this rule is usually linked to automated software (e.g. Amazon CloudWatch ) to raise more virtual resources from

18765-566: The web server. Much like Slowloris, RUDY keeps sessions at halt using never-ending POST transmissions and sending an arbitrarily large content-length header value. Manipulating maximum segment size and selective acknowledgement (SACK) may be used by a remote peer to cause a denial of service by an integer overflow in the Linux kernel, potentially causing a kernel panic . Jonathan Looney discovered CVE - 2019-11477 , CVE- 2019-11478 , CVE- 2019-11479 on June 17, 2019. The shrew attack

18904-454: The web. Marketed and promoted as stress-testing tools, they can be used to perform unauthorized denial-of-service attacks, and allow technically unsophisticated attackers access to sophisticated attack tools. Usually powered by a botnet, the traffic produced by a consumer stresser can range anywhere from 5-50 Gbit/s, which can, in most cases, deny the average home user internet access. A Markov-modulated denial-of-service attack occurs when

19043-512: Was an anonymous centralized IRC server. Freenet is a censorship -resistant distributed data store . I2P is an anonymous peer-to-peer distributed communication layer designed to run any traditional internet service (e.g. Usenet , email , IRC , file sharing , Web hosting and HTTP , or Telnet ), as well as more traditional distributed applications (e.g. a distributed data store, a web proxy network using Squid , or DNS ). Many developers of I2P are known only under pseudonyms . While

19182-408: Was necessary to launch the attack. A system may also be compromised with a trojan containing a zombie agent . Attackers can also break into systems using automated tools that exploit flaws in programs that listen for connections from remote hosts. This scenario primarily concerns systems acting as servers on the web. Stacheldraht is a classic example of a DDoS tool. It uses a layered structure where

19321-542: Was thought to be an attack executed by an unnamed customer of the US-based service provider Arbor Networks , reaching a peak of about 1.7 Tb/s . In February 2020, Amazon Web Services experienced an attack with a peak volume of 2.3 Tb/s . In July 2021, CDN Provider Cloudflare boasted of protecting its client from a DDoS attack from a global Mirai botnet that was up to 17.2 million requests per second. Russian DDoS prevention provider Yandex said it blocked

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