Malicious code in tinkoff-statist-browser-typed-client-sme.users.origination.web (npm)
The package's main entry require()'s _loader.js, which at import time downloads a per-platform binary from string-concatenation-obfuscated Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev), with a DNS-TXT chunk-reassembly fallback over subdomains of dl.well1.site. The fetched bytes are written to a disguised path under /var/tmp or %TEMP% (e.g..cache_<hex> or dotnet_diag_<hex>.exe), chmod'd to 0755 via bracketed property access (fs["chmod"+"Sync"]), and executed detached via cp.spawn("/bin/sh", ["-c", path + " &"]) or cp.spawn("cmd.exe", ["/c", "start", "/b", path]). API names and hostnames are hidden behind array-join concatenation (require("child_"+"process"), ["oob-worker",".cf103-070.w","orkers.dev"].join("")) to evade static detection. A second copy of the dropper is shipped in lib/telemetry.js under an "Analytics SDK" cover story, using the same primitives (base64-chunk Buffer assembly, disk write, chmod 0755, /bin/sh spawn). The fetched payload is opaque, unpinned, unverified, and delivered from non-publisher-controlled infrastructure with a covert DNS channel; the destinations do not match the package's declared scope (a Tinkoff-branded internal typed client).
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
MAL-2026-12277 is recorded against 1 package.
Published on 5 August 2026 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
Details
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| tinkoff-statist-browser-typed-client-sme.users.origination.web | — | — |
References
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