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Malicious package

bigops-file-storagenpm

Advisory published Updated

bigops-file-storage is a confirmed malicious npm package (MAL-2026-12167) that opens a backdoor for remote access (malicious version 35.1.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in bigops-file-storage (npm)

MAL-2026-12167
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall bigops-file-storage

What this malware does

On require() of bigops-file-storage, index.js loads vendor.js which selects a platform-specific asset path, fetches an opaque native binary over HTTPS from attacker-controlled Cloudflare Workers subdomains (oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-TXT chunked fallback under *.sdk.dl.wel1.ru, writes it to a temp cache path, chmods 0755 on POSIX, and spawns it detached via /bin/sh -c or cmd.exe /c start /b. The C2 hostnames and the child_process module name are reconstructed at runtime from split-string arrays joined together, and dropper strings are framed under cover names ('analytics_state', 'dotnet_diag'). A duplicate copy of the same download-decode-chmod-spawn pipeline is shipped in lib/telemetry.js under an 'analytics SDK' framing (base64 chunk assembly, fs['chmod'+'Sync'](extensionPath, mode|0o755), cp.spawn('/bin/sh', ['-c', filePath + ' &'], {detached:true})) as an alternate/staged loader. The package advertises itself as a file-storage adapter but ships no such functionality — it is purely a dropper that runs on import and executes attacker-supplied native code on the installer's host.

Malicious versions

1 flagged
35.1.2

Indicators of compromise (SHA-256)

ff4d23505ef5dd8a734e25b08b9b86a98bdf482482a2dbffcdf34f1467a2aa82

Detection & response playbook

Backdoor / remote access
  1. Find it

    Search your lockfiles and build artifacts for bigops-file-storage (version 35.1.2).

  2. If you installed it — respond

    bigops-file-storage establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

  3. Did it already run?

    If bigops-file-storage was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. bigops-file-storage on npm has been identified as a malicious package (version 35.1.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-014406

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks bigops-file-storage-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Explore

bigops-file-storage (npm) malicious package — MAL-2026-12167 | O3 Security