Cybersecurity researchers have uncovered over 40 malicious browser extensions for Mozilla Firefox which might be designed to steal cryptocurrency pockets secrets and techniques, placing customers’ digital belongings in danger.
“These extensions impersonate official pockets instruments from widely-used platforms reminiscent of 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 alleged to have been ongoing since a minimum of April 2025, with new extensions uploaded to the Firefox Add-ons retailer as just lately as final week.
The recognized extensions have been discovered to artificially inflate their recognition, including tons of of 5-star opinions that go far past the entire variety of energetic installations. This technique is employed to offer them an phantasm of authenticity, making it appear to be they’re broadly adopted and tricking unsuspecting customers into putting in them.
One other tactic adopted by the menace actor to bolster belief includes passing off these add-ons as official pockets instruments, utilizing the identical names and logos.
The truth that among 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.
In contrast to typical phishing scams that depend on faux web sites or emails, these extensions function contained in the person’s browser—making them far tougher to detect or block with conventional endpoint instruments.
“This low-effort, high-impact strategy allowed the actor to take care of anticipated person expertise whereas decreasing the probabilities of instant 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 menace actor group.
All of the recognized add-ons except 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 acquire recognition amongst customers and are used to steal customers’ belongings by tricking them into coming into their credentials.
To mitigate the danger 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.
