Old Worm, New Tricks: FacexWorm Targets Crypto Platforms

FacexWorm, a malicious Chrome extension, has been rediscovered targeting cryptocurrency trading platforms and spreading via Facebook Messenger. The Cyber Safety Solutions team at Trend Micro reports it's packing a few new capabilities, including the ability to steal user data.

The extension was first detected in August 2017 and returned the following April amid reports of increased appearances in Germany, Tunisia, Japan, Taiwan, South Korea, and Spain. Like the original, it sends socially-engineered links to friends of affected Facebook account holders.

Unlike the original, it steals accounts and credentials related to FacexWorm's targeted sites. The attack takes potential victims to websites where it injects malicious cryptomining code and redirects to the attacker's referral link for crypto-related referral programs. It hijacks transactions in trading platforms by replacing the recipient address with the attacker's.

The attacker gets a referral incentive every time a victim registers an account, researchers report. Targeted websites include Binance, DigitalOcean, FreeBitco.in, FreeDoge.co.in, and HashFlare.

FacexWorm arrives on victims' machines via socially-engineered Facebook links. Those who click are redirected to a fake YouTube page where they are prompted to install a codec extension (FacexWorm) to play a video. The extension requests privilege to access and edit data on the site.

If permission is granted, FacexWorm downloads malicious codes from its command-and-control server, opens Facebook's website, and checks to see if the propagation function is turned on. If it is, the extension requests an OAuth token from Facebook and begins obtaining the target account's friend list. Contacts who are online or idle are sent fake YouTube links.

"FacexWorm is a clone of a normal Chrome extension but injected with short code containing its main routine," explains Trend Micro fraud researcher Joseph Chen in a blog post on the finding. The threat downloads more code from the C&C server when the browser is opened.

"Every time a victim opens a new webpage, FacexWorm will query its C&C server to find and retrieve another JavaScript code (hosted on a Github repository) and execute its behaviors on that webpage." This JavaScript code, or miner, is an obfuscated Coinhive script connected to a Coinhive pool, configured to use 20% of the target system's CPU power for each threat.

FacexWorm exhibits other malicious behaviors like stealing account credentials for Google, MyMonero, and Coinhive. This threat targets a total of 52 cryptocurrency platforms. When it detects anyone accessing any of them or using keywords like "blockchain" or "ethereum" in the URL, it redirects the user to a fraudulent webpage.

This threat only works in Chrome. If the malicious link is accessed through any browser other than the Chrome desktop version, it redirects to a random advertisement. Trend Micro has only spotted one Bitcoin transaction compromised by FacexWorm based on monitoring the attacker's wallet. Researchers haven't determined how much money the threat has generated.