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The growing security threat to virtual systems

Security threats to virtualized environments is not a new subject, but it’s one that should be gaining prominence as organizations, and particularly those in government, virtualize more in order to cut costs and improve IT efficiencies. If agencies don’t consider the security implications, they’re opening themselves up to a world of hurt.

That’s especially true since the world of malware innovators is not standing still, as a new report from Symantec points out. As fast as defenses are erected, attackers come up with ways to get around them.

One of the more recent exploits involves attacks that are designed to wait out the automatic malware detection and analysis defenses that are increasingly being built into virtual systems. Some trojans will simply wait for multiple mouse clicks to occur before they decrypt themselves and start up their payload, and that can make it all but impossible for automated systems to come to any timely conclusion about the threat.

“Time is on [the malware’s] side,” said Candid Wüest, author of the Symantec report. “If the sample does not behave maliciously within the first five to 10 minutes, the analysis system will most likely deem the file as harmless.”

This in turn has prompted attackers to develop other methods of evading automated analysis on virtual machines, such as focusing more on the user’s interaction. The malware waits, for example, for three left-button clicks on the mouse before executing. In that case any kind of user interaction, say the use of a CAPTCHA box, a test to determine if a user is human, could prompt action.

Those kinds of exploits are harder to patch on virtual machines and require some background monitoring to generate the necessary interaction triggers, Wüest said.

The most complete government guide to virtualization security is NIST’s three-year old SP 800-125 Guide to Security for Full Virtualization Technologies. It says that the security of a full virtualization solution is heavily dependent on the individual security of its components – from hypervisor and host operation systems to applications and storage. Other sound security practices, such as keeping up to date with security patches, are also necessary.

That’s all true, but it doesn’t seem to be enough in the face of what appears to be an inevitable push by malware designers into the virtual space. And it could be that virtualization attacks are now an embedded feature in most malware. Up to 82 percent of the malware tracked by Symantec was able to run on virtual machines.

It’s not as if organizations haven’t been warned. As long ago as 2009, the Cloudburst Attack showed how attackers could go through a guest virtual machine to attack the host, in many ways an IT administrator’s worst nightmare. In 2012, the Crisis malware, which targeted Windows and Mac systems, was shown to also be capable of sneaking onto virtual machines if a specific image was installed on it.

Given the range of threats now facing virtualized environments, Symantec recommends a number of best practices for organizations to follow:

  • Protect the host server, which provides access to virtual machines, with lockdown solutions and host intrusion detection systems along with regular software updates and patches.
  • Protect both the host server and virtual machines running on it with “proactive” components that go beyond classic security such as antivirus scanners.
  • Have administrators enforce proper user access controls to the servers hosting virtual machines and use two-factor authentication or other strong login processes.
  • Make sure the virtual machines are fully integrated into disaster recovery and business continuity plans.
  • Network security tools should also have access to the virtual network traffic between the virtual machines.
  • Snapshots and images of virtual machines need to be included in the patch and upgrade cycle. Unpatched virtual machines are frequent targets of malware.
  • Integrate virtual machines into the security logging and security information and event management (SIEM) systems that are used for all other IT devices.

The overall message, which NIST stresses, is that the security of virtual machines and networks needs to be handled just as intensely as that of other IT. Given the rate of innovation on the malware side, that might not be all that’s needed, but it will go a long way.

Posted by Brian Robinson on Aug 29, 2014 at 11:58 AM


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