Unless you?ve been off the Internet for the last seven years, you?ve probably heard of the massive security problem: botnets. These networks of infected computers commanded by criminal outfits can launch coordinated attacks, host malicious websites or send spam - lots of it.
One of the biggest spamming botnets out there is Pushdo, a botnet that despite being responsible for 7.7 billion spammed emails per day worldwide, has managed to stay under the radar since 2007. It has even managed to make it consistently to the Top 5 largest botnets without ever reaching number one, and is the Top 2 largest spamming botnets worldwide. Poor Pushdo, always the bridesmaid, never the bride!
In reality the Pushdo botnet is a very fancy software distribution platform. Once the victim is infected, Pushdo phones home asking for a bunch of malware executables, a lot of which are third party malware. This is the only kind of communication with the command & control server; no P2P components, just very frequent updates from the central server, one typically hosted in the US. Pushdo seems to have missing out compared to Storm and Downad, but its complete lack of self-propagation and simple C&C structure does not seem to have hampered it in the least.