Which versions of cobrowsing-configs are malicious?

The following npm versions of cobrowsing-configs are flagged malicious: 35.7.5. Treat any of these as compromised.

How do I remediate cobrowsing-configs if I installed it?

cobrowsing-configs 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.

I already installed cobrowsing-configs — how do I know if it already compromised me?

If cobrowsing-configs 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.

Is cobrowsing-configs part of a known attack campaign?

Yes — cobrowsing-configs is associated with the IN-MAL-2026-015127 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find cobrowsing-configs across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for cobrowsing-configs (version 35.7.5).

Malicious package

cobrowsing-configsnpm

Advisory published Aug 5, 2026Updated Aug 5, 2026

cobrowsing-configs is a confirmed malicious npm package (MAL-2026-12652) that opens a backdoor for remote access (malicious version 35.7.5). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in cobrowsing-configs (npm)

MAL-2026-12652

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall cobrowsing-configs

What this malware does

On require() of cobrowsing-configs, index.js loads polyfill.js which downloads a platform-specific binary from hardcoded Cloudflare Workers endpoints (oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS TXT-record fallback channel under dl.wel1.ru (sdk.dl.wel1.ru, net.dl.wel1.ru). The destination hostnames are assembled at runtime by joining split string fragments to evade static analysis. The fetched bytes are written to /tmp or %TEMP% under deceptive names impersonating system artifacts (e.g., dotnet_diag.exe,.cache_), chmod 0755 on Unix, and executed detached via spawn("/bin/sh", ["-c",...]) or spawn("cmd",...). No hash or signature verification is performed, and the fetched binary is unrelated to the package's stated purpose of loading configuration. The behavior fires as a side effect of importing the module, giving whoever controls the C2 hosts arbitrary code execution on any machine that installs and loads the package.

Malicious versions

1 flagged

35.7.5

Indicators of compromise (SHA-256)

45bae002aa55664445a0af3da60cf5187e91f09e77eee63b2da3d4840b30d558

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for cobrowsing-configs (version 35.7.5).
If you installed it — respond
cobrowsing-configs 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.
Did it already run?
If cobrowsing-configs 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. cobrowsing-configs on npm has been identified as a malicious package (version 35.7.5 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015127

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

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

Malware detection Runtime egress monitoring

Explore

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