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Chrome Is Scanning Files on Your Computer

The browser you likely use to read this article scans practically all files on your Windows computer. And you probably had no idea until you read this. Don’t worry, you’re not the only one.

Last year, Google announced some upgrades to Chrome, by far the world’s most used browser—and the one security pros often recommend. The company promised to make internet surfing on Windows computers even “cleaner” and “safer ” adding what The Verge called “basic antivirus features.” What Google did was improve something called Chrome Cleanup Tool for Windows users, using software from cybersecurity and antivirus company ESET.

Tensions around the issue of digital privacy are understandably high following Facebook’s Cambridge Analytica scandal, but as far as we can tell there is no reason to worry here, and what Google is doing is above board.

In practice, Chome on Windows looks through your computer in search of malware that targets the Chrome browser itself using ESET’s antivirus engine. If it finds some suspected malware, it sends metadata of the file where the malware is stored, and some system information, to Google. Then, it asks you to for permission to remove the suspected malicious file. (You can opt-out of sending information to Google by deselecting the “Report details to Google” checkbox.)

A screenshot of the Chrome pop-up that appears if Chrome Cleanup Tool detects malware on your Windows computer.

A screenshot of the Chrome pop-up that appears if Chrome Cleanup Tool detects malware on your Windows computer.

Last week, Kelly Shortridge, who works at cybersecurity startup SecurityScorecard, noticed that Chrome was scanning files in the Documents folder of her Windows computer.

“In the current climate, it really shocked me that Google would so quietly roll out this feature without publicizing more detailed supporting documentation—even just to preemptively ease speculation,” Shortridge told me in an online chat. “Their intentions are clearly security-minded, but the lack of explicit consent and transparency seems to violate their own criteria of ‘user-friendly software’ that informs the policy for Chrome Cleanup [Tool].”

Her tweet got a lot of attention and caused other people in the infosec community—as well as average users such as me—to scratch their heads.

“Nobody likes surprises,” Haroon Meer, the founder at security consulting firm Thinkst, told me in an online chat. “When people fear a big brother, and tech behemoths going too far…a browser touching files it has no business to touch is going to set off alarm bells.”

Now, to be clear, this doesn’t mean Google can, for example, see photos you store on your windows machine. According to Google, the goal of Chrome Cleanup Tool is to make sure malware doesn’t mess up with Chrome on your computer by installing dangerous extensions, or putting ads where they’re not supposed to be.

As the head of Google Chrome security Justin Schuh explained on Twitter, the tool’s “sole purpose is to detect and remove unwanted software manipulating Chrome.” Moreover, he added, the tool only runs weekly, it only has normal user privileges (meaning it can’t go too deep into the system), is “sandboxed” (meaning its code is isolated from other programs), and users have to explicitly click on that box screenshotted above to remove the files and “cleanup.”

In other words, Chrome Cleanup Tool is less invasive than a regular “cloud” antivirus that scans your whole computer (including its more sensitive parts such as the kernel) and uploads some data to the antivirus company’s servers.

But as Johns Hopkins professor Matthew Green put it, most people “are just a little creeped out that Chrome started poking through their underwear drawer without asking.”

That’s the problem here: most users of an internet browser probably don’t expect it to scan and remove files on their computers.

When reached out for comment, a Google spokesperson redirected me to the blog post from last year and Schuh’s tweets.

A section in Chrome’s Privacy Whitepaper explains that “Chrome periodically scans your device to detect potentially unwanted software.” That exact language has been there since at least January of 2017, according to archived versions of the whitepaper. And similar language (“Chrome scans your computer periodically for the sole purpose of detecting potentially unwanted software”) has been there for even longer.

Martijn Grooten, the editor of Virus Bulletin and organizer of one of the premiere antivirus conferences in the world, told me in a Twitter chat that the behavior of the Chrome Cleanup Tool was “sensible.”

“For almost all users, this seems really harmless, and for those who are extremely concerned about Google seeing some metadata, maybe they shouldn’t be running Google’s browser in the first place,” he said.

Motherboard

Hackers can get rich using your computer — and you’d never know it

It’s getting hard to read the news without hearing about another cyber attack making its way around the global internet.

A growing trend among cybercriminals is the kind of malware attack that infiltrates your network and works quietly in the background to perform tasks such as mining a digital currency and sending the profits back to the author of the virus while the host remains unaware.

This type of threat has been highlighted by the Adylkuzz attack which exploits the same Microsoft vulnerability as the WannaCry attack. However, where WannaCry seized files and ransomed them, Adylkuzz installs a cryptocurrency miner on compromised machines.

“These are not particularly unusual, we see a lot of malware that does cryptocurrency mining,” Nick Savvides, a security specialist at Symantec told News.com.au. “There’s a very big business in it.”

Such malware can often go undetected but will likely degrade a computer’s performance and speed.

“If criminals get it right it doesn’t chew up too many resources, just enough that it can deliver something,” and the infection can go undetected for long periods of time.

Given the rising value of many cryptocurrencies in recent months, “it’s possible to make quite a bit of money out of it without it being noticed,” Savvides said.

After security firm Proofpoint published a blog this week describing how the attack turns infected users into unwitting financial supporters of cyber criminals, some reports claimed the Adylkuzz malware could end up being a bigger attack than WannaCry which infected as many as 200,000 Windows systems in more the 150 countries. But Savvides disagrees.

“I just don’t see it. The reason I don’t see it is that this has been active for some time now, the rates of infection have been pretty low, and there hasn’t been an associated e-mail campaign to infect hosts,” he said.

Proofpoint said it has detected a number of infected machines that have transferred several thousand dollars worth of the cryptocurrency Monero to the creators of the virus dating back to as early as April 24.

Interestingly, once the malware exploits the Microsoft vulnerability, it shuts it down, thus denying anyone else the chance to do the same. “One bad guy making sure no one else can steal his host.”

These types of attacks share certain characteristics with the commonly used distributed denial of service (DDoS) attacks which also take control of unwitting hosts to direct their computer’s traffic at a particular network.

“In fact as a cybercriminal, you could dual purpose that botnet. You could go and infect thousands of hosts and utilize them to not just mine bitcoins for you but to also launch a denial of service attack for you,” Savvides said.

These kind of attacks “aren’t going away.”

So if your computer is running a little slower than usual, how can you check if it might possibly be compromised?

According to Savvides the only thing the average person can do to ensure they’re not the unwitting victim of such malware is to run a security tool like Norton Power Eraser which is a free virus and malware removal tool that people can run to clean their device.

“I think that’s really the only way for a layman to determine this,” he said.

New York Post