Two days ago Symantec fixed a massive security vulnerability in its Anti-Virus Engine (AVE). The last thing you want when you install security software is to make your system less secure and that's exactly what happened.
The bug consists of a buffer overflow condition that could be triggered when parsing executable files with malformed headers. Cybercriminals could very easily exploit the bug, all it took was tricking users to open a link or sending a malicious e-mail. Executing the file wasn't even necessary because the antivirus engine automatically scans all incoming e-mails, and to make matters even worse, the anti-virus engine unpacks such files inside the kernel, leading to a full system compromise.
Google security engineer Tavis Ormandy discovered the vulnerability. Symantec patched it in the Anti-Virus Engine (AVE) version 20188.8.131.52, released Monday via LiveUpdate.
“On Linux, Mac and other UNIX platforms, this results in a remote heap overflow as root in the Symantec or Norton process,” Ormandy said in an advisory. “On Windows, this results in kernel memory corruption, as the scan engine is loaded into the kernel, making this a remote ring0 memory corruption vulnerability—this is about as bad as it can possibly get.”