OpenSourceMalware Show #28 Covers Claude Code, Binance, Polymarket and PolinRider
Summary
Episode 28 discusses a trojanized Claude Code extension distributed via Cursor's Open VSX mirror, Binance's reported $6.3 billion crypto theft, Polymarket's reported compromise via DebugBear, and evidence suggesting PolinRider activity in 2025.
Key points
- A trojanized Claude Code extension distributed through Cursor's Open VSX mirror enabled persistent remote access and searched for cloud credentials; the hosts said exposure depended on obtaining it through Cursor.
- Binance's retrospective described a June malicious Homebrew download, a September fake-interview coding assignment, access to two more developer machines, and use of a deployment token on October 29.
- The hosts said roughly $3 billion of an attempted $6.3 billion crypto theft was frozen. They reported that the FBI linked the incident to North Korea based on infrastructure shared with the Bybit attack.
- The hosts said there was no evidence establishing PolinRider's involvement in the Binance attack.
- Polymarket was reportedly compromised through malicious JavaScript delivered via DebugBear after the vendor's DNS records were hijacked at its domain registrar; public details remained limited.
- A compromised npm package from May 2025 contained an obfuscated payload resembling PolinRider, but the speakers differed on whether it was an early campaign instance or a precursor; gaps in repository history limited certainty.
- The hosts said PolinRider filenames, extensions and locations have changed, recommending detection based on more stable campaign markers and review of VS Code tasks.json files with run-on-folder-open commands.
Article Details
- Event Type
- Software supply-chain compromises and cryptocurrency theft
- Impact
- A trojanized Claude Code extension gave attackers persistent remote access; a reported $6.3 billion was stolen from Binance, with roughly $3 billion frozen; and Polymarket was compromised through malicious JavaScript delivered via DebugBear. Researchers also identified a suspected early PolinRider payload in npm packages compromised in May 2025.
MITRE ATT&CK
T1195.002 · Compromise Software Supply ChainA trojanized extension and compromised npm packages delivered malicious code through software supply chains.T1199 · Trusted RelationshipPolymarket was compromised through malicious JavaScript from third-party provider DebugBear after its DNS records were hijacked.
People
Malware
Vendors
Anthropic(blog) Security notice: malicious version of Anthropic.claude-code (2.1.312 and 2.1.313) identified in the Cursor VS Code Extension MarketplaceCursorTrojanized Claude Code extension: On October 29, a trojanized Claude Code extension was shipped from Cursor's own mirror of the Open VSX registry. Cursor's mirror can carry different versions than Open VSX itself, soDebugBearPolymarket compromised through DebugBear: Polymarket was compromised through malicious JavaScript from DebugBear, a third-party vendor whose DNS records were hijacked at its domain registrar.
Products
Claude CodeTrojanized Claude Code extension: On October 29, a trojanized Claude Code extension was shipped from Cursor's own mirror of the Open VSX registry. Cursor's mirror can carry different versions than Open VSX itself, soCursorTrojanized Claude Code extension: On October 29, a trojanized Claude Code extension was shipped from Cursor's own mirror of the Open VSX registry. Cursor's mirror can carry different versions than Open VSX itself, soDebugBearPolymarket compromised through DebugBear: Polymarket was compromised through malicious JavaScript from DebugBear, a third-party vendor whose DNS records were hijacked at its domain registrar.HomebrewBinance robbed by North Korea: The $6.3 billion Binance crypto theft started in June, when an engineer downloaded a malicious version of Homebrew.PolymarketPolymarket compromised through DebugBear: Polymarket was compromised through malicious JavaScript from DebugBear, a third-party vendor whose DNS records were hijacked at its domain registrar.