There were over 3 million impressions on malicious Web advertisements in the final quarter of 2010, as a result of poor vetting by ad networks and social media.
The number of malicious Web
advertisements jumped sharply in the fourth quarter of 2010, according to a
report from security firm Dasient.
"Malvertising," or
advertisements containing malware, was on the rise, with more than 3 million
impressions per day in the fourth quarter, double what was found in the third
quarter, Dasient said in its 2010 Malware Report, released Mar. 7.
Attackers were increasingly
sneaking malicious code and links to malware-laden Websites within malicious
ads that legitimate advertising networks were distributing to a large number of
Websites. Security experts predict that these ads would increase in 2011 as a
very easy and lucrative attack vector.
Part of the increase in
Dasient's report may be attributed to the fact that the company decided to
include remnant ad networks in the survey for the first time. Remnant networks
sell empty advertising slots for a low rate so that other advertising networks
have another pool of ads to draw upon instead of relying on house ads to fill
empty inventory, Dasient said. These third-party ad networks aggregate
advertisements and generally have very low ad rates, so they are less likely to
vet such advertisements carefully, the report said.
"With the addition of more
remnant ad networks in our telemetry, we believe that we are more accurately
reflecting the current state of malvertsing," the report stated.
Malvertising can wreak havoc
on unsuspecting Website visitors without going through the trouble of hacking
the actual Website. Such was the case recently when visitors to the London
Stock Exchange Website were hit by rogue anti-virus malware served up by a
malicious ad that appeared on the site.
As part of the research,
Dasient researchers conducted several "benign" experiments to see how malware
was being spread. Researchers posted an ad whose click-through links pointed to
a Website that automatically triggered a drive-by-download, Dasient said. The
file being downloaded was safe, the researchers said. The benign ad had the
headline, "Click for a security test," was linked to "hackerhome.org" and opened
up the Windows calculator if the computer was vulnerable. Researchers said
various social-networking sites kept the ad up for more than three weeks.
Social networks are also not
screening their ad landing pages with automated systems that look for drive-by downloads
of malware, said Dasient.
Firms that serve
advertisements need to do a better job vetting the content of the images they
distribute for malicious code and detecting Web-based attacks, including
malicious ads, when they appear, said Neil Daswani, Dasient's CTO.
The researchers also tested
how easy it was to spread malware via malicious links on social-network sites.
More than 80 percent of the social-networking sites allowed links that were on
Google's Safe Browsing list to pass, and all the sites allowed links that
triggered a drive-by download, the researchers said. Most social-media networks
do not check links in UGC (user-generated content) such as posts and comments
to determine if they contain or lead to malware threats, the report found.
It was clear that infections
could occur relatively easily via UGC interactions and advertisements,
according to researchers.
More than a million Websites
were infected with malware in the fourth quarter of 2010, nearly double those of
the last quarter 2009, according to the report.
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