AV-Test - 22 million unique malware test samples in June 2009

Polymorphism is a technique used to create unique variants from the same malware agent.  for example, through random number generators and other techniques, each wave of attacks can be slightly different.

This approach is designed to trick AV scanning engines and sometimes slightly different AV signatures must be added. AV detection is very complex and a must have on every PC and Server. 

The 22 samples and graphs in this article reflect the difficulty AV vendors have in keeping up on a daily basis.  It's why we must also update our PCs as well.

AV-Test - 22 million malware samples in June due to Polymorphism
http://www.avertlabs.com/research/blog/index.php/2009/07/24/counting-badness/

QUOTE: AV-Test counts unique binaries. Unique means different cryptographic hashes. So the same Trojan, obfuscated with 10 different packers results in 10 unique binaries. This is often due to the impact of server-side polymorphism, where you get a unique binary every time you download a file

AV-Test’s count has come close to 22,000,000 samples in June. We are now seeing a major increase in the monthly growth, topping one million new samples each month in AV-Test’s count. And this time it’s not only samples (the same piece of malware packed over and over again) but also actual new malware.

So keep your machine updated, not just AV and the OS but all applications. Watch out where you surf. (SiteAdvisor may help you there.) And take care what links or attachments you trust in emails and all other forms of messages. All this will help you enjoy the summer!