"Critical vulnerabilities have been found this year in virtually all antivirus products. But the danger of protective software, of all things, mutating into a gateway for pests is still largely underestimated. Antivirus software is not only the most important protection against pests arriving from the Internet, it could also be one of the most dangerous gateways for attackers and their damaging software.
Not only does it run on every desktop system, it’s also present on many servers and is constantly processing potentially malicious files. So a security hole at this point could have catastrophic consequences.
In a presentation (PDF file) at Hack.lu 2007, Sergio Alvarez and Thierry Zoller criticized poor security precautions in antivirus software in particular. These two security specialists from n.runs know what they are talking about: in 2007 alone they published about thirty advisories on security problems in antivirus software, some of them critical. They allege that they notified some 800 problems to manufacturers." Antivirus software as a malware gateway – heise Security