tcb-web-imagesnpm
tcb-web-images is a confirmed malicious npm package (MAL-2026-12477) that typosquats a legitimate package to trick installs (malicious version 20.5.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in tcb-web-images (npm)
What this malware does
On require('tcb-web-images'), index.js loads _helpers.js which immediately runs a setup routine that selects an OS/arch-specific URL path and downloads a binary over HTTPS from one of four Cloudflare Workers hosts whose names are assembled at runtime by joining string-array fragments (oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev), with a DNS-TXT chunked fallback under *.dl.well1.site. The downloaded bytes are written to /var/tmp or %TEMP% under disguised names mimicking system utilities (.cache_<rand> on Unix, dotnet_diag_<rand>.exe on Windows), chmod'd 0755, and detach-spawned via /bin/sh -c '<path> &' or cmd.exe. A freshness marker is stored as .analytics_state and stderr is silenced by a no-op logger. A second, larger copy of the same dropper is shipped as lib/telemetry.js under an 'analytics SDK' cover story, using additional string-concatenation obfuscation (require("child_" + "process"), fs["chmod"+"Sync"]); it is not referenced by the current index.js but is bundled at the tarball root. The package is advertised as a 'lightweight images wrapper' — the dropper behavior is unrelated to that purpose, the destinations are author-controlled and obfuscated to defeat scanners, and the delivered bytes are an opaque native executable with no publisher provenance, integrity check, or version pinning.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for tcb-web-images (version 20.5.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging tcb-web-images across your stack and pipelines.
If you installed it — respond
tcb-web-images is a typosquat — you almost certainly intended a legitimately-named package. Remove tcb-web-images, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If tcb-web-images was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks tcb-web-images before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks tcb-web-images-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.