Google's Android Malware Detection Falls Short

Android appears to be on a trajectory to become the Windows of mobile operating systems, but there's a downside to ubiquity. Rising market share means increasing attention from malware authors.

Sophos, a computer security company, asserts that there is a growing malware problem for Android devices and that Android devices are less safe than iOS or Windows Phone devices. The FBI has noticed too, issuing a warning in October about risks facing Android users.

Google appears to be aware that Android needs better security. In September, it bought VirusTotal.com, a company that measures the effectiveness of malware detection engines. And Android 4.2 "Jelly Bean" includes a new app verification service to help identify potentially malicious apps.

[ Will Apple products be more secure if they are made in the United States? Read Apple Mac To Be Made In USA. ]

But a study published recently by Xuxian Jiang, associate professor of computer science at North Carolina State University, finds that Google's app verification service can identify only 15% to 20% of known Android malware.

The study also found that existing third-party security software for Android -- from Avast, AVG, TrendMicro, Symantec, BitDefender, ClamAV, F-Secure, Fortinet, Kaspersky and Kingsoft -- performed significantly better at detecting malware, with accuracy ranging from 51% to 100%.

In his study, Jiang says that the app verification service's reliance on SHA1 cryptographic hashes to identify malware files "is fragile and can be easily bypassed." Malware authors can simply repackage or alter their files to create different hash values, a fact that had forced the creators of computer security products to look beyond signature-based solutions.

Jiang suggests that Google's cloud-based approach to security could be augmented by more on-device security capabilities. In an email, he said the app verification service can be considered a move toward enhancing client-side security, but the "signature-based approach (adopted in most of current AV systems) can never keep up with the speed at which malware is created and evolved."

He recommends that Google look into collecting more information about apps, inasmuch as privacy considerations allow. He also says Google should "beef up the app verification service or integrate with more advanced server support," through integration with Bouncer, an app scanning mechanism that Google introduced in February, or Google's newly acquired VirusTotal.com.

Google didn't immediately respond to a request for comment.