Blue Coat protects users from new fake anti-virus attack by web advertisements


Blue Coat Systems, a provider of Web security and WAN
optimization solutions, announced that Blue Coat Security Labs has identified a
new variant of a fake anti-virus attack that uses Web advertisements to relay
users into the Shnakule network, which is currently the largest and most
effective Malware Delivery Network on the Internet.


The Blue Coat WebPulse service identified the fake
anti-virus payloads as malware and automatically blocked them, protecting 75
million customers worldwide.


The Shnakule network has averaged around 2,000 unique
host names per day with as many as 4,357 in a single day. On an average day,
the WebPulse service logs more than 21,000 requests into that network.


Shnakule has been very active with fake anti-virus
attacks typically conducted via search engine poisoning. With this latest
attack, it is now using malvertising to conduct its attacks. To date, the Blue
Coat WebPulse service has identified more than 15,000 user requests related to
the latest form of the attack.


The latest Shnakule attack is a three-staged attack that
utilizes malicious Web advertisements. In the first stage, malicious ad servers
were set up as independent entities, not directly associated with each other or
any existing Shnakule sub-networks, to route users to malware.


In the second stage, a new Shnakule subnetwork relays
users to the malware. The final stage is the malware payload, which changes
frequently in an attempt to avoid detection from anti-virus software.


The malware payload comes from servers that have already
been identified by WebPulse as part of the Shnakule Malware Delivery Network.
Because of its visibility into the Shnakule network, the Blue Coat WebPulse
service was already blocking the malware payload before the attack was


“Though this attack initially launched in late June,
it is still continuing, and in a recent check of the payload by Blue Coat
Security Labs against 43 anti-virus engines only two of those engines
identified the payload as malicious or suspicious,” said Chris Larsen,
senior malware researcher for Blue Coat Systems.


Web-based malware changes far too quickly these days for
traditional single-layer defenses like anti-virus to keep pace. The most
successful defense against this type of attack is one like WebPulse that can
correlate the evidence and automatically identify and block the network
responsible, regardless of how the payload is encrypted.


In the current attack, none of the rogue ad servers
appears by name in the pages that host its ads, indicating that the victimized
legitimate sites are not directly using these ad servers.


Each of the rogue ad servers had been set up with
different registrars at least a month prior to launching the attack, which was
long enough to successfully convince Web advertising companies that they were
serving legitimate ads.


The Blue Coat WebPulse service is a collaborative defense
that provides proactive threat protection for 75 million users worldwide. With
more than three billion requests per week, WebPulse has a comprehensive view of
user activity on the Web.


By correlating dynamic lures with relays and malware
payloads, Blue Coat can identify and block Malware Delivery Networks and the
future attacks they launch.


By Team
[email protected]