Malware goes to the movies
While video files, as entertainment, evoke less suspicion on the part of users, they also have a number of disadvantages.
In the world of data, video files are the lumbering cruise liners, the Titanics. For standard TV quality video, a 30-second clip may only require downloading 2Mb to 3Mb, but a 23 minute TV episode weighs in at a third of a gigabyte, and a full-length movie can easily top a gigabyte. A video of any appreciable length contains enough bits to slow down a home internet connection to a crawl, though more highly compressed video takes up less bandwidth.
The sheer size of such files make them a less appealing target, said OffensiveComputing's Smith.
"I think users are a bit more likely to open a video file but they are also a little harder to transport around because of their size," he said. "Often malware authors want something small."
The cross-platform nature of video files also makes them less appealing, Smith said. An attacker would either have to target an exploit for a single platform or attempt to encode the file in such a way as to work on different systems. In the 40,000 samples of malware that OffensiveComputing has in its database, none use video as an infection vector, he said.
Not only is video harder for an attacker to use, the files are easier for a defender to secure, said Adrian Ludwig, senior manager for secure software engineering at Adobe.
"The threat models for video are far more well understood," Ludwig said. "It is either a good piece of video or it's not."
Run-of-the-mill Flash content, which contains scripting and is event driven, can be far more complex, Ludwig said. Flash-creator Macromedia - and then Adobe, which bought the company in April 2005 - has increasingly focused on the security of the multimedia technology as its popularity grew.
"We have been responding to the issues for many years now, and I think we put out releases as fast as anyone else," Ludwig said.
In the end, while virus writers are currently experimenting with video files, other media files will likely become more popular, said McAfee's Schmugar.
"As more users adopt any technology, that's where there attacker will go," McAfee's Schmugar said. "It is a little early to say it is the beginning of a trend, but it's safe to say that we expect to see continued attention on media files as a vector."
This article originally appeared in Security Focus.
Copyright © 2006, SecurityFocus
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