LWA-2026-10467 MAL-2026-12689 ↗ confirmed malware

delivery-ci-validate-tinkoff-fb@35.6.9

Malicious code in delivery-ci-validate-tinkoff-fb (npm)

T1059.007 · JavaScriptT1059 · Command and Scripting InterpreterT1105 · Ingress Tool TransferT1071.001 · Web ProtocolsT1102 · Web ServiceT1082 · System Information Discovery

Analysis

The package runs a multi-stage downloader on require. index.js loads _adapter.js, which fingerprints the OS and downloads a second-stage binary over HTTPS from Cloudflare Workers hosts oob-worker[.]cf101-adf[.]workers[.]dev, oob-worker[.]cf100-416[.]workers[.]dev, oob-worker[.]cf102-baf[.]workers[.]dev, and oob-worker[.]cf103-070[.]workers[.]dev (paths /pkg/package, /pkg/package-arm64, /pkg/loader_mac, /pkg/package.exe). If the HTTPS download fails it retrieves the payload via DNS TXT queries against sdk[.]dl[.]wel1[.]ru / ext[.]dl[.]wel1[.]ru / pkg[.]dl[.]wel1[.]ru / net[.]dl[.]wel1[.]ru. The downloaded binary is written to /var/tmp/.cache_<hex> (or dotnet_diag_<hex>.exe in the temp dir on Windows), made executable, and launched as a detached background process via cmd.exe /c start /b or /bin/sh -c "<path> &". A state file at /tmp/.analytics_state throttles repeat execution.

analyzed by
Leitwacht
first seen
Aug 5, 2026, 01:30 PM
analyzed
Aug 5, 2026, 04:33 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.