Forty malicious Firefox extensions have been discovered impersonating legitimate Web3 products like OKX and Rabby Wallet as part of a campaign called "Offside Wallet Theft Factory," believed to have been active since March 2026. The extensions steal cryptocurrency wallet secrets — including recovery phrases and private keys — using methods such as fake wallet pages, hidden malicious code, and exfiltration via Cloudflare Workers and Supabase. Some extensions initially appeared as innocent sports score or utility tools before being repurposed as wallet-stealing malware, with researchers noting that the low cost of repeatedly publishing disposable extensions makes the campaign highly scalable and persistent.
