Which versions of cobrowsing-logger are malicious?

The following npm versions of cobrowsing-logger are flagged malicious: 35.7.7. Treat any of these as compromised.

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

cobrowsing-logger is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

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

If cobrowsing-logger 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.

Is cobrowsing-logger part of a known attack campaign?

Yes — cobrowsing-logger is associated with the IN-MAL-2026-015114 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-logger across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for cobrowsing-logger (version 35.7.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging cobrowsing-logger across your stack and pipelines.

Malicious package

cobrowsing-loggernpm

cobrowsing-logger is a confirmed malicious npm package (MAL-2026-12656) that steals credentials and exfiltrates sensitive data (malicious version 35.7.7). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in cobrowsing-logger (npm)

MAL-2026-12656

Immediate action

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

npm uninstall cobrowsing-logger

What this malware does

index.js unconditionally requires _adapter.js on load. _adapter.js reconstructs destination hostnames from string-split fragments (assembling oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, and sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru at runtime), platform-branches on the host OS, downloads an opaque executable over HTTPS with a DNS-TXT base64 fallback under the *.dl.wel1.ru zone, writes it to /tmp or %TEMP% under a decoy filename (.cache_<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe. An opt-out branch is gated on generic-telemetry environment variables to mimic benign analytics behavior. The dropped binary is not shipped in the tarball and is not verified by hash or signature; whatever the operator of the Workers hosts / DNS-TXT channel serves at fetch time runs detached on the installer's machine on every require('cobrowsing-logger').

Malicious versions

1 flagged

35.7.7

Indicators of compromise (SHA-256)

8d5fcbe415de738c1434d79c5b40d1afb7ea916b5ed4b7103b29e244e27169ea

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for cobrowsing-logger (version 35.7.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging cobrowsing-logger across your stack and pipelines.
If you installed it — respond
cobrowsing-logger is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If cobrowsing-logger 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 cobrowsing-logger 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

No. cobrowsing-logger on npm has been identified as a malicious package (version 35.7.7 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015114

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

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

Malware detection Runtime egress monitoring

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