Which versions of cobrowsing-decorators are malicious?

The following npm versions of cobrowsing-decorators are flagged malicious: 35.2.9. Treat any of these as compromised.

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

Remove cobrowsing-decorators from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

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

If cobrowsing-decorators 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-decorators part of a known attack campaign?

Yes — cobrowsing-decorators is associated with the IN-MAL-2026-015124 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-decorators 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-decorators (version 35.2.9). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging cobrowsing-decorators across your stack and pipelines.

Malicious package

cobrowsing-decoratorsnpm

cobrowsing-decorators is a confirmed malicious npm package (MAL-2026-12653) that executes malicious code on install (malicious version 35.2.9). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in cobrowsing-decorators (npm)

MAL-2026-12653

Immediate action

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

npm uninstall cobrowsing-decorators

What this malware does

On require/import, index.js unconditionally loads bootstrap.js, which selects a platform-specific asset path, fetches an opaque binary from string-concatenation-obfuscated Cloudflare Workers endpoints (oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev) with a DNS TXT fallback to sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru, writes it to a disguised temp filename (dotnet_diag*.exe,.analytics_state), chmods it 0755 on POSIX, and spawns it detached via /bin/sh -c or cmd. No signature or hash verification is performed and the payload has no relationship to the package's declared 'cobrowsing decorators' purpose. lib/telemetry.js (81 KB, framed as an 'Analytics SDK') replicates the same dropper primitives — base64 chunk assembly, fs.chmodSync to 0755 via string-concatenated method name, and detached cp.spawn('/bin/sh', ['-c', filePath + ' &']) — providing a redundant execution path. Endpoint hostnames and fallback domains are assembled by joining fragmented substrings to evade plain-string review.

Malicious versions

1 flagged

35.2.9

Indicators of compromise (SHA-256)

bdc5e76564b50cf17ba170a2f1da7cae4ab386277b4a03e64e79ec34e1276588

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for cobrowsing-decorators (version 35.2.9). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging cobrowsing-decorators across your stack and pipelines.
If you installed it — respond
Remove cobrowsing-decorators from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If cobrowsing-decorators 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-decorators 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-decorators on npm has been identified as a malicious package (version 35.2.9 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015124

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks cobrowsing-decorators-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.

Malware detection Runtime egress monitoring

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