Cybersecurity researchers have uncovered over 40 malicious browser extensions for Mozilla Firefox which are designed to steal cryptocurrency pockets secrets and techniques, placing customers’ digital property in danger.
“These extensions impersonate professional pockets instruments from widely-used platforms similar to Coinbase, MetaMask, Belief Pockets, Phantom, Exodus, OKX, Keplr, MyMonero, Bitget, Leap, Ethereum Pockets, and Filfox,” Koi Safety researcher Yuval Ronen stated.
The massive-scale marketing campaign is claimed to have been ongoing since at the very least April 2025, with new extensions uploaded to the Firefox Add-ons retailer as lately as final week.
The recognized extensions have been discovered to artificially inflate their recognition, including a whole lot of 5-star critiques that go far past the overall variety of lively installations. This technique is employed to offer them an phantasm of authenticity, making it appear to be they’re extensively adopted and tricking unsuspecting customers into putting in them.
One other tactic adopted by the risk actor to bolster belief entails passing off these add-ons as professional pockets instruments, utilizing the identical names and logos.
The truth that a few of the precise extensions have been open-source allowed the attackers to clone their supply code and inject their very own malicious performance to extract pockets keys and seed phrases from focused web sites and exfiltrate them to a distant server. The rogue extensions have additionally been discovered to transmit the victims’ exterior IP addresses.
Not like typical phishing scams that depend on faux web sites or emails, these extensions function contained in the consumer’s browser—making them far more durable to detect or block with conventional endpoint instruments.
“This low-effort, high-impact strategy allowed the actor to keep up anticipated consumer expertise whereas lowering the possibilities of quick detection,” Ronen stated.
The presence of Russian language feedback within the supply code in addition to metadata obtained from a PDF file retrieved from the command-and-control (C2) server used for the exercise factors to a Russian-speaking risk actor group.
All of the recognized add-ons aside from MyMonero Pockets have since been taken down by Mozilla. Final month, the browser maker stated it has developed an “early detection system” to detect and block rip-off crypto pockets extensions earlier than they achieve recognition amongst customers and are used to steal customers’ property by tricking them into coming into their credentials.
To mitigate the chance posed by such threats, it is suggested to put in extensions solely from verified publishers and vet them to make sure that they do not silently change their conduct post-installation.
