Norton Anti-Virus (NAV) allows remote attackers to bypass content filtering via attachments whose Content-Type and Content-Disposition headers are mixed upper and lower case, which is ignored by some mail clients.
The default configurations for McAfee Virus Scan and Norton Anti-Virus virus checkers do not check files in the RECYCLED folder that is used by the Windows Recycle Bin utility, which allows attackers to store malicious code without detection.