LWA-2026-10571 MAL-2026-12654 ↗ confirmed malware

cobrowsing-exception-filter@35.8.3

Malicious code in cobrowsing-exception-filter (npm)

T1059.007 · JavaScriptT1105 · Ingress Tool TransferT1071.001 · Web ProtocolsT1102 · Web ServiceT1059 · Command and Scripting Interpreter

Analysis

On require, the package downloads a platform-specific binary from Cloudflare Workers endpoints (oob-worker[.]cf100-416[.]workers[.]dev, oob-worker[.]cf99-9b3[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev, oob-worker[.]cf103-070[.]workers[.]dev) at paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe, with a DNS-TXT fallback channel via *.dl[.]wel1[.]ru (c[.]sdk[.]dl[.]wel1[.]ru, ext[.]dl[.]wel1[.]ru, pkg[.]dl[.]wel1[.]ru, net[.]dl[.]wel1[.]ru). The fetched binary is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe on Windows), made executable, and launched as a detached background process (cmd.exe start /b on Windows, /bin/sh -c '... &' on Unix). Execution is rate-limited by a marker file at /tmp/.analytics_state.

analyzed by
Leitwacht
first seen
Aug 5, 2026, 08:10 PM
analyzed
Aug 5, 2026, 08:11 PM

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Independently detected by the Leitwacht supply-chain probe. IOCs are defanged. Published CC0. Think this is a mistake? See the dispute policy.