Bitcoin group newspapers
43 comments
Jaron lanier bitcoin exchange
A botnet is a number of Internet -connected devices, each of which is running one or more bots. Botnets can be used to perform distributed denial-of-service attack DDoS attack , steal data, [1] send spam, and allows the attacker to access the device and its connection. The term is usually used with a negative or malicious connotation.
A botnet is a logical collection of internet-connected devices such as computers, smartphones or IoT devices whose security has been breached and control ceded to a third party. Each such compromised device, known as a "bot", is created when a device is penetrated by software from a malware malicious software distribution. The controller of a botnet is able to direct the activities of these compromised computers through communication channels formed by standards-based network protocols such as IRC and Hypertext Transfer Protocol HTTP.
Botnets are increasingly rented out by cyber criminals as commodities for a variety of purposes. Botnet architecture has evolved over time in an effort to evade detection and disruption. Traditionally, bot programs are constructed as clients which communicate via existing servers. This allows the bot herder the person controlling the botnet to perform all control from a remote location, which obfuscates their traffic.
These P2P bot programs perform the same actions as the client-server model, but they do not require a central server to communicate. The first botnets on the internet used a client-server model to accomplish their tasks. Typically, these botnets operate through Internet Relay Chat networks, domains, or websites. Infected clients access a predetermined location and await incoming commands from the server. The bot herder sends commands to the server, which relays them to the clients.
Clients execute the commands and report their results back to the bot herder. The bot herder sends commands to the channel via the IRC server. Each client retrieves the commands and executes them. Clients send messages back to the IRC channel with the results of their actions. In response to efforts to detect and decapitate IRC botnets, bot herders have begun deploying malware on peer-to-peer networks.
These bots may use digital signatures so that only someone with access to the private key can control the botnet. Gameover ZeuS and ZeroAccess botnet. Newer botnets fully operate over P2P networks. Rather than communicate with a centralized server, P2P bots perform as both a command distribution server and a client which receives commands.
In order to find other infected machines, the bot discreetly probes random IP addresses until it contacts another infected machine. The contacted bot replies with information such as its software version and list of known bots.
If one of the bots' version is lower than the other, they will initiate a file transfer to update. A botnet's originator known as a " bot herder " or "bot master" controls the botnet remotely.
The program for the operation which must communicate via a covert channel to the client on the victim's machine zombie computer. A bot herder creates an IRC channel for infected clients to join. Messages sent to the channel are broadcast to all channel members. The bot herder may set the channel's topic to command the botnet.
Some botnets implement custom versions of well-known protocols. The implementation differences can be used for detection of botnets. In computer science, a zombie computer is a computer connected to the Internet that has been compromised by a hacker, computer virus or trojan horse and can be used to perform malicious tasks of one sort or another under remote direction.
Botnets of zombie computers are often used to spread e-mail spam and launch denial-of-service attacks. Most owners of zombie computers are unaware that their system is being used in this way. Because the owner tends to be unaware, these computers are metaphorically compared to zombies. A coordinated DDoS attack by multiple botnet machines also resembles a zombie horde attack. Many computer users are unaware that their computer is infected with bots. The process of stealing computing resources as a result of a system being joined to a "botnet" is sometimes referred to as "scrumping.
Bots are added to the botnet by using a scanning script, the scanning script is run on an external server and scans IP ranges for telnet and SSH server default logins. Once a login is found it is added to an infection list and infected with a malicious infection line via SSH on from the scanner server.
When the SSH command is run it infects the server and commands the server to ping to the control server and becomes its slave from the malicious code infecting it. These types of botnets were used to take down large websites like Xbox and PlayStation network by a known hacking group called Lizard Squad. IRC networks use simple, low bandwidth communication methods, making them widely used to host botnets. They tend to be relatively simple in construction and have been used with moderate success for coordinating DDoS attacks and spam campaigns while being able to continually switch channels to avoid being taken down.
However, in some cases, the mere blocking of certain keywords has proven effective in stopping IRC-based botnets. One problem with using IRC is that each bot client must know the IRC server, port, and channel to be of any use to the botnet. Anti-malware organizations can detect and shut down these servers and channels, effectively halting the botnet attack. If this happens, clients are still infected, but they typically lie dormant since they have no way of receiving instructions. If one of the servers or channels becomes disabled, the botnet simply switches to another.
It is still possible to detect and disrupt additional botnet servers or channels by sniffing IRC traffic. A botnet adversary can even potentially gain knowledge of the control scheme and imitate the bot herder by issuing commands correctly. Some have also used encryption as a way to secure or lock down the botnet from others, most of the time when they use encryption it is public-key cryptography and has presented challenges in both implementing it and breaking it.
Many large botnets tend to use domains rather than IRC in their construction see Rustock botnet and Srizbi botnet. They are usually hosted with bulletproof hosting services. A zombie computer accesses a specially-designed webpage or domain s which serves the list of controlling commands. Disadvantages of using this method are that it uses a considerable amount of bandwidth at large scale, and domains can be quickly seized by government agencies without much trouble or effort.
If the domains controlling the botnets are not seized, they are also easy targets to compromise with denial-of-service attacks. Fast-flux DNS can be used as a way to make it difficult to track down the control servers, which may change from day to day. While these free DNS services do not themselves host attacks, they provide reference points often hard-coded into the botnet executable.
Removing such services can cripple an entire botnet. Newer bots can automatically scan their environment and propagate themselves using vulnerabilities and weak passwords. Generally, the more vulnerabilities a bot can scan and propagate through, the more valuable it becomes to a botnet controller community. Computers can be co-opted into a botnet when they execute malicious software.
This can be accomplished by luring users into making a drive-by download , exploiting web browser vulnerabilities , or by tricking the user into running a Trojan horse program, which may come from an email attachment. This malware will typically install modules that allow the computer to be commanded and controlled by the botnet's operator. After the software is downloaded, it will call home send a reconnection packet to the host computer.
When the re-connection is made, depending on how it is written, a Trojan may then delete itself or may remain present to update and maintain the modules.
In some cases, a botnet may be temporarily created by volunteer hacktivists , such as with implementations of the Low Orbit Ion Cannon as used by 4chan members during Project Chanology in China's Great Cannon of China allows the modification of legitimate web browsing traffic at internet backbones into China to create a large ephemeral botnet to attack large targets such as GitHub in The botnet controller community features a constant and continuous struggle over who has the most bots, the highest overall bandwidth, and the most "high-quality" infected machines, like university, corporate, and even government machines.
While botnets are often named after the malware that created them, multiple botnets typically use the same malware but are operated by different entities. Host-based techniques use heuristics to identify bot behavior that has bypassed conventional anti-virus software.
BotHunter is software, developed with support from the U. Army Research Office , that detects botnet activity within a network by analyzing network traffic and comparing it to patterns characteristic of malicious processes. Researchers at Sandia National Laboratories are analyzing botnets' behavior by simultaneously running one million Linux kernels—a similar scale to a botnet—as virtual machines on a 4,node high-performance computer cluster to emulate a very large network, allowing them to watch how botnets work and experiment with ways to stop them.
One thing that's becoming more apparent is the fact that detecting automated bot attacks is becoming more difficult each day as newer and more sophisticated generations of bots are getting launched by attackers. For example, an automated attack can deploy a large bot army and apply brute-force methods with highly accurate username and password lists to hack into accounts. The idea is to overwhelm sites with tens of thousands of requests from different IPs all over the world, but with each bot only submitting a single request every 10 minutes or so, which can result in more than 5 million attempts per day.
One of the techniques for detecting these bot attacks is what's known as "signature-based systems" in which the software will attempt to detect patterns in the request packet.
But attacks are constantly evolving, so this may not be a viable option when patterns can't be discerned from thousands of requests. There's also the behavioral approach to thwarting bots, which ultimately is trying distinguish bots from humans.
By identifying non-human behavior and recognizing known bot behavior, this process can be applied at the user, browser, and network levels. The first botnet was first acknowledged and exposed by Earthlink during a lawsuit with notorious spammer Khan C. Around , to thwart detection, some botnets were scaling back in size. From Wikipedia, the free encyclopedia. The Future of Botnets in the Internet of Things". Retrieved 28 July Retrieved 9 June Retrieved 12 November Retrieved 28 June Handbook of Information and Communication Security.
Uses authors parameter link CS1 maint: Retrieved 2 September Retrieved 27 May Russian hackers target the cloud, Twitter, GitHub in malware spread". Retrieved 7 October