Antivirus programs on PCs have a mixed track record. While generally useful, they still have to play catch-up with evolving threats–and their deep system access has on occasion enabled even worse attacks. Now, as antivirus products gain in popularity for Android devices, they appear to be making many of the same old mistakes.
A key part of the current shortcomings stems from relative immaturity in Android antivirus offerings. Researchers at Georgia Tech who analyzed 58 mainstream options found that many were relatively easy to defeat, often because didn’t take a nuanced and diverse approach to malware detection. Taking on the mindset of an attacker, the researchers built a tool called AVPass that works to smuggle malware into a system without being detected by antivirus. Of the 58 programs AVPass tested, only two–from AhnLab and WhiteArmor–consistently stopped AVPass attacks.
“Antivirus for the mobile platform is really just starting for some companies—a lot of the antivirus for Android may even be their first iteration,” says Max Wolotsky, a PhD student at Georgia Tech who worked on the research. “We would definitely warn consumers that they should look into more than just AV. You want to be cautious.”
Modern antivirus uses machine-learning techniques to evolve with the malware field. So in creating AVPass, the researchers started by developing methods for defeating defensive algorithms they could access (like those created for academic research or other open-source projects) and then used these strategies as the basis for working out attacks against proprietary consumer antivirus—products where you can’t see the code powering them. The team will present on and release AVPass at the Black Hat hacking conference in Las Vegas on Thursday.
To test the 58 Android antivirus products and figure out what bypasses would work against each of them, the researchers used a service called VirusTotal, which attempts to identify links and malware samples by scanning them through a system that incorporates dozens of tools, and offering results about what each tool found. By querying VirusTotal with different malware components and seeing which tools flagged which samples, the researchers were able to form a picture of the type of detection features each antivirus has. Under an academic license, VirusTotal limited the group to fewer than 300 queries per malware sample, but the researchers say even this small number was adequate for gathering data on how the different services go about detecting malware.