Posted by Virus Bulletin on Sep 14, 2011
Files with code-executing properties attached to emails.
Researchers at Symantec have discovered Windows Help Files being used in targeted attacks.
Such help files, which use the .hlp extension, are used by Windows Help, a program that allows users to find help for programs running on the popular operating system. Because the files can call the Windows API, they have been used for malicious purposes for a long time. However, this is the first time they have been attached to emails.
Because of the ability of such files to call the API, malware authors do not have to exploit vulnerabilities. On the other hand, there may be few legitimate reasons for attaching .hlp files to emails, and developers of email security software may want to consider blocking such attachments by default - thus protecting their users from falling victim to such an attack.
Targeted attacks, often referred to as Advanced Persistent Threats (APT), have led to a lot of debate in the anti-malware industry. Some experts claim that this is the most important threat for larger organizations, while others believe the threat is exaggerated and that many such attacks use methods that are far from advanced. In a panel discussion at VB2011, experts will discuss how the industry should approach such attacks.
More at Symantec's blog here.