By Joris Evers
Staff Writer, CNET News.com
August 4, 2006
LAS VEGAS -- Reading blogs via popular RSS or Atom feeds may expose
computer users to hacker attacks, a security expert warns.
to subscribers of data feeds that use the popular RSS (Really Simple
Syndication) or Atom formats, Bob Auger, a security engineer with Web
security company SPI Dynamics, said Thursday in a presentation at the
Black Hat security event here.
The problem doesn't affect only blogs--any kind of information feed using
any kind of format could potentially be used to transmit malicious content
to a subscriber, Auger said. People, for example, subscribe to mailing
lists and news Web sites via RSS, he said, noting "this is about the
entire concept of Web feeds."
SPI Dynamics examined a number of online and offline applications used to
the feed would run on the user's PC, meaning it could be vulnerable to
increasingly causing security concerns.
Attackers could exploit the problem by setting up a malicious blog and
enticing a user to subscribe to the RSS feed. More likely, however, they
said. "A lot of blogs will take user comments and stick them into their
own RSS feeds," he said.
Also, attackers could send malicious code to mailing lists that offer RSS
or Atom feeds and commandeer vulnerable systems that way, Auger said.
Feeds are popular because they let people consolidate information streams
from multiple sites, such as blogs, in one application, called a feed
reader, removing the need to surf to multiple sites.
Many of the popular feed reading applications are faulted because the
designers have failed to add valuable security checks, Auger said. In
in feeds to run. Instead, it should be filtered out, he said.
Additionally, some reader software on Windows systems uses Internet
Explorer to display feed content, but doesn't use basic security settings
and has full access, which can fully expose a person's PC, Auger said.
"A large percentage of the readers I tested had some kind of an issue," he
said. In his presentation, Auger listed Bloglines, RSS Reader, RSS Owl,
Feed Demon, and Sharp Reader as vulnerable.
As protection, people could switch to a nonvulnerable reader. Also, feed
publishers could ensure that their feeds don't include malicious
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