Malicious code in tcb-web-images (npm)
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (1e4ea2872f88d974e66cc870c5fbfbf92294eb63026155a96bea567a096f4d69) 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. ## Source: ghsa-malware (c1380a3b63e9f71c1a3d2d58040216fe5ffc0a0b27291d8d4596224f1ee6aa64) 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.
AI Analysis
Technical Summary
The 'tcb-web-images' npm package (version 20.5.3) includes a malicious payload embedded in its index.js and an additional dropper in lib/telemetry.js. Upon requiring the package, it downloads a native executable from dynamically assembled Cloudflare Workers URLs or a DNS-TXT fallback domain. The executable is saved under disguised filenames in temporary directories, given executable permissions, and launched detached from the main process. The package uses string concatenation obfuscation to evade detection and does not perform any integrity verification on the downloaded binary. The delivered payload is opaque with no publisher provenance, indicating a high risk of malicious activity unrelated to the package's advertised functionality.
Potential Impact
Systems that install and run 'tcb-web-images' version 20.5.3 risk executing an unauthorized native binary that could perform arbitrary actions on the host. The binary is downloaded from attacker-controlled infrastructure, executed with minimal visibility, and could compromise system integrity or confidentiality. The lack of integrity checks or publisher verification increases the risk of undetected malicious activity.
Mitigation Recommendations
No official patch or remediation is currently documented for this malicious package version. Users should immediately remove 'tcb-web-images' version 20.5.3 from their environments and avoid installing this package. Investigate any systems where this package was installed for signs of compromise. Use trusted sources and verify package provenance before installation. Monitor for updates from the package maintainer or npm advisories for any official remediation.
Malicious code in tcb-web-images (npm)
Description
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (1e4ea2872f88d974e66cc870c5fbfbf92294eb63026155a96bea567a096f4d69) 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. ## Source: ghsa-malware (c1380a3b63e9f71c1a3d2d58040216fe5ffc0a0b27291d8d4596224f1ee6aa64) 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.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The 'tcb-web-images' npm package (version 20.5.3) includes a malicious payload embedded in its index.js and an additional dropper in lib/telemetry.js. Upon requiring the package, it downloads a native executable from dynamically assembled Cloudflare Workers URLs or a DNS-TXT fallback domain. The executable is saved under disguised filenames in temporary directories, given executable permissions, and launched detached from the main process. The package uses string concatenation obfuscation to evade detection and does not perform any integrity verification on the downloaded binary. The delivered payload is opaque with no publisher provenance, indicating a high risk of malicious activity unrelated to the package's advertised functionality.
Potential Impact
Systems that install and run 'tcb-web-images' version 20.5.3 risk executing an unauthorized native binary that could perform arbitrary actions on the host. The binary is downloaded from attacker-controlled infrastructure, executed with minimal visibility, and could compromise system integrity or confidentiality. The lack of integrity checks or publisher verification increases the risk of undetected malicious activity.
Mitigation Recommendations
No official patch or remediation is currently documented for this malicious package version. Users should immediately remove 'tcb-web-images' version 20.5.3 from their environments and avoid installing this package. Investigate any systems where this package was installed for signs of compromise. Use trusted sources and verify package provenance before installation. Monitor for updates from the package maintainer or npm advisories for any official remediation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- MAL-2026-12477
- Osv Schema Version
- 1.7.4
- Ecosystems
- ["npm"]
Threat ID: 6a735746bf8831d53915a030
Added to database: 08/05/2026, 15:31:18 UTC
Last enriched: 08/05/2026, 17:31:54 UTC
Last updated: 09/07/2026, 22:24:06 UTC
Views: 18
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