A Google Site Meant to Protect You Is Helping Hackers Attack You

Before companies like Microsoft and Apple release new software, the code is reviewed and tested to ensure it works as planned and to find any bugs.

Hackers and cybercrooks do the same. The last thing you want if you’re a cyberthug is for your banking Trojan to crash a victim’s system and be exposed. More importantly, you don’t want your victim’s antivirus engine to detect the malicious tool.

So how do you maintain your stealth? You submit your code to Google’s VirusTotal site and let it do the testing for you.

It’s long been suspected that hackers and nation-state spies are using Google’s antivirus site to test their tools before unleashing them on victims. Now Brandon Dixon, an independent security researcher, has caught them in the act, tracking several high-profile hacking groups—including, surprisingly, two well-known nation-state teams—as they used VirusTotal to hone their code and develop their tradecraft.

“There’s certainly irony” in their use of the site, Dixon says. “I wouldn’t have expected a nation state to use a public system to do their testing.”

VirusTotal is a free online service—launched in 2004 by Hispasec Sistemas in Spain and acquired by Google in 2012—that aggregates more than three dozen antivirus scanners made by Symantec, Kaspersky Lab, F-Secure and others. Researchers, and anyone else who finds a suspicious file on their system, can upload the file to the site to see if any of the scanners tag it malicious. But the site, meant to protect us from hackers, also inadvertently provides hackers the opportunity to tweak and test their code until it bypasses the site’s suite of antivirus tools.

Dixon has been tracking submissions to the site for years and, using data associated with each uploaded file, has identified several distinct hackers or hacker teams as they’ve used VirusTotal to refine their code. He’s even been able to identify some of their intended targets.

He can do this because every uploaded file leaves a trail of metadata available to subscribers of VirusTotal’s professional-grade service. The data includes the file’s name and a timestamp of when it was uploaded, as well as a hash derived from the uploader’s IP address and the country from which the file was submitted based on the IP address. Though Google masks the IP address to make it difficult to derive from the hash, the hash still is helpful in identifying multiple submissions from the same address. And, strangely, some of the groups Dixon monitored used the same addresses repeatedly to submit their malicious code.

Using an algorithm he created to parse the metadata, Dixon spotted patterns and clusters of files submitted by two well-known cyberespionage teams believed to be based in China, and a group that appears to be in Iran. Over weeks and months, Dixon watched as the attackers tweaked and developed their code and the number of scanners detecting it dropped. He could even in some cases predict when they might launch their attack and identify when some of the victims were hit—code that he saw submitted by some of the attackers for testing later showed up at VirusTotal again when a victim spotted it on a machine and submitted it for detection.

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