"Malware authors have been using evasive techniques for years, and those techniques are becoming more and more complex," said Chris Kruegel, Chief Scientist at Lastline. "It's a game of cat and mouse as once a solution to an evasive threat is discovered, the malware authors go back to the drawing board and find another way to avoid detection."
The report highlights two techniques currently used by malware authors: Environmental Checks and Stalling Code. While environmental checks have been well documented, stalling code is the latest technique being utilized to spread malware. It delays the execution of a malicious code inside a sandbox and instead performs a computation that appears legitimate. Once the sandbox has timed out, the evasive malware is free to execute. The report finds that stalling codes are particularly troublesome because they "can no longer be handled by traditional sandboxes (even if the trick is known)."
"Current sandboxes have a lack of visibility into the execution of a malware program," said Giovanni Vigna, CTO of Lastline. "To detect this new breed of evasive threats, a sandbox needs to have visibility and must be able to do this stealthily. Otherwise, as we have seen in stalling code, the malware will react accordingly and remain undetectable."
Lastline offers a solution in the form of a system emulator, which allows the company to "gain the advantages of a virtual execution environment, while retaining the "ability to see every instruction." According to the report, this type of solution is "crucial to be able to automatically handle environmental checks as well as stalling code."
For a full copy of "The Security Threat of Evasive Malware" and to learn more about Lastline, please visit: www.lastline.com
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Lastline protects networks against target attacks, APT's, and zero-day targeted attacks across all threat vectors. Lastline's malware defense solution performs high-resolution analysis of incoming threats and outgoing network traffic, and combines this with active discovery of the threat landscape (the malscape.) The result is actionable threat intelligence that enables effective remediation.
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