Three Most Active Botnets Spewing 21 Billion Spam Daily

According to the MessageLabs Intelligence Report from Symantec, three most active botnets i.e. armies of zombie PCs under hackers' control, are spewing massive 21 Billion spam mails daily.

The botnets, which contain compromised computers, are - Cutwail, Mega-D and Donbot, all competing to acquire the title of 'top spam distributor.' The botnets are already sending 15-20% of the total worldwide spam, the company stated.

Nevertheless, Cutwail was withdrawn from its spamming operations for a short period during August 1-2, 2009 as Real Host (the Latvian ISP) was shut down, but after that, the botnet started spamming at its original levels. Nevertheless, Donbot is still causing troubles. This one ran 3 extra spam campaigns, with one accounting for a high 9.25% of the total global spam on July 28, 2009.

In the meantime, hackers are expanding their collection of bots by compromising systems, which are without antivirus protection. Operators of the systems might find their computers running slow, but they do not find extra evidence that tells them about the infection in their systems. This gives an impression that it has been turned into a drone.

Experts state - the bot herders could use these botnets to launch distributed denial-of-service (DDoS) attacks in which every single bot overwhelms an Internet site with repeated requests. However, to remain protected from such an attack, a company often has to block the individual bots' IP addresses.

Moreover, these DDoS attacks are nowadays rapidly increasing in number, with cyber crooks using them to covertly take hold over unsecured PCs and then rent those computers out as bots to others. While an estimated 14 Million PCs have been hijacked via this method, a standard botnet consists of several thousand zombies.

Furthermore, in the latest instance of a botnet assault, cyber criminals targeted the social-networking websites Facebook, LiveJournal and Twitter on August 6, 2009 when the attack spanned over several hours.

Facebook said - it experienced problems on its network that related to a DDoS attack, leading to service disruption to some users while Twitter provided users an only notification that it was doing everything possible to defend its site from the attack.

Related article: Three New Threats With Highest Percentages in Top Ten

» SPAMfighter News - 8/25/2009