Bots & Botnets

From Computing and Software Wiki

A Botnet is a collection of infected computers that can be used to attack organizations and distribute illegal information due to the sheer number of computers that is contained within them. Botnets are hard to prevent as the computers usually bear no resemblance in their locations in the physical world.

Contents 1 Definitions 1.1 Bot 1.2 Herder 1.3 Zombie 1.4 Scrumping 2 How it works 3 Attacks 3.1 DDoS 3.2 Spamming 3.3 Phishing 4 Life Cycle 5 Bot Management 6 How to Fight Botnets 6.1 Norton Anti-Bot 7 References 8 See Also 9 External Links

Definitions

• Bot
• Herder
• Zombie
• Scrumping

Bot

A Bot is short for robot. In the context of this wikipedia page a bot is a malicious program that installs itself unbeknowenst to the owner of the pc, sets up an IRC or HTTP server and is ready to perform illegal activities.

Herder

A person who controls all the bots in the botnet.

Zombie

An infected computer.

Scrumping

A bot stealing CPU cycles from the host computer.

How it works

A Botnet basically uses a command and control schema, the same as a military. Each bot has a chain of command that is part of. It distributes orders down the line that it recieves from up top. This is benificial in the fact that it can grow exponentially. This is the opposite of the cell schema that some malware uses, which is to split apart and never communicate once they become big enough.

A bot installs itself onto a pc. It has various vectors that the Herder can set. It does this autonomously. It recieves orders from a server that tell it what to do. An individual bot by itself is not that powerful. However an exponential number of bots performing the same action has a much more profound effect.

Attacks

• DDoS
• Spamming
• Phishing

DDoS

A Distributed denial of Service attack. The bots flood a web server with ICMP requests causing the server to crash. This can be used as a method of extortion from various websites. The herder demonstrates the power of his botnet by taking down the website, then he/she contacts the site in question and extorts them for money.

Spamming

A Herder can sell his botnet as a service to a spammer. This is beneficial to the spammer as he can have anonymous distribution of his messages.

Phishing

Works the same way as the spamming method.

Life Cycle

• Intial setup of configuration settings of the bot
• Register a Dynamic DNS
• Infect a PC with a bot
  • Bot propagates according to the configuration settings
  • Scans for vunerabilities
  • Idle
  • Performs actions as recieved by other bots above it in the chain of command
  • Bot dies:
    • Bot may be taken over by another botnet
    • The bot's owner's pc realizes the pc is a zombie, kills the bot.
    • The chain of command may be compromised above the level.

Bot Management

They commonly have hidden removal commands, to completely clean the host computer. On the larger IRC networks such as EFnet channel activity is logged in order to learn the commands, and then automated systems are setup to prevent the owner of the botnet from accessing them and at the same time perform the removal command when a bot comes online to it's control channel.

How to Fight Botnets

Norton Anti-Bot

Norton Anti-Bot is commercial software that scans your system to see if it has become a zombie. It is behavioural based, versus the usual signature based. What this means is unless the bot software actually does something, Norton will leave it alone. It has all the benefits of a commercial software, meaning it will be updated constantly as new bot definitions are found.

References

"Botnet"

See Also

"Alternative Technologies for Ethernet"

External Links

http://www.symantec.com/norton/products/overview.jsp?pcid=is&pvid=nab1