The effectiveness of malicious code is largely determined by whether or not it’s detected by anti-virus scanners. By replicating the scans of leading security products using test tools located on underground forums and web pages, miscreants gain the chance to fine-tune their creations to make sure they aren’t picked up by anti-virus heuristic (generic) detection.
The Underground tools foil generic virus detection | The Register
http://theregister.co.uk”>underground tools are technically similar to Hispasec’s legitimate Virus Total tool, according to Spanish anti-virus firm Panda Software. It notes that the increased interest in underground testing tools coincides with the removal of the “do not distribute the sample” option in Virus Total. The now compulsory feature means that samples of files scanned by Virus Total are sent to security firms.
Back in the day malware authors wanted to make a name for themselves by causing trouble; these days they’re more interested in making sure of extending the half-life of money-making malware by making sure it attracts the minimum of attention and, as far as possible, creeps in under the radar of anti-virus tools. Non-disclosure testing of malware toolkits prior to this release aids this process, as well as creating income for unscrupulous coders happy to work for VXers.