Miscreants have released a Trojan specially designed to disable cloud-based anti-virus security defences.
The Bohu blocks connections from infected Windows devices and cloud anti-virus services in place to protect them. Malware writers have long included routines to disable components of desktop anti-virus software packages or block access to anti-virus websites from infected machines.
More and more security firms are beginning to adopt cloud-based anti-virus architectures, as they offer the twin benefits of a lesser performance overhead (all the heavy lifting is done on servers in the cloud not on the client) and faster response to the growing volume of malware threats. Bohu reflects the fact that the bad guys have once again adopted to the changes applied by security defenders.
Bohu - which was spotted by anti-virus researchers working for Microsoft in China - is hardwired to block access to cloud-based net services from Kingsoft, Qihoo, and Rising. All three firms are based in China.
The malware poses as a video codec, a common ruse by virus writers worldwide. If installed, Bohu applies a filter that blocks traffic between the infected machines and service provider. The malware also includes routines to hide its presence on infected machines.
Microsoft security researchers described Bohu as "art of the first wave of malware that specifically targets cloud-based anti-virus technology", in a detailed write-up of the threat on the Microsoft Malware Protection Center blog.
Anti-virus firms have added detection for the malware, which ought to block infection providing the latest signature updates have been applied.
Alan Bentley, SVP International of security tools firm Lumension, argued that the approach taken by Bohu is likely to be replicated by other strains of Trojan, both in China and elsewhere.
"Bohu is not just another piece of malware," Bentley said. "It is the first designed to target anti-virus technology that is protecting the cloud. Add to that the fact that it is native to China, and we are seeing yet another new wave of targeted cyber attacks.
"With the bad guys now targeting security defences, a different approach to safeguarding data is required. Relying on anti-virus solutions has proven ineffective time and time again.
A more intelligent approach to security would serve to prevent against attacks like Bohu. Only by allowing code that is known to be good to enter a network, can organisations make sure they are truly protected." ®