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, Blue Coat Systems said. 

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, it said.

The latest Shnakule attack is a three-staged attack that utilises 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 launched.

“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 Nigel Hawthorn, vice president EMEA marketing at 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.”  - TradeArabia News Service