Mal/HTMLGen-A is the threat name associated with web pages that have been classified as malicious by SophosLabs.
Web pages blocked by Sophos products as Mal/HTMLGen-A are likely to be present in an infection chain aimed at downloading and executing malware on a user's machine. This tactic is used by exploit kits such as the Blackhole Exploit Kit.
A detection of Mal/HTMLGen-A indicates that access to a web page has been blocked by Sophos Live URL filtering.