Which versions of express-router-engine are malicious?

The following npm versions of express-router-engine are flagged malicious: 3.6.5, 3.6.6, 3.6.7. Treat any of these as compromised.

How do I remediate express-router-engine if I installed it?

express-router-engine 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 express-router-engine — how do I know if it already compromised me?

If express-router-engine 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 express-router-engine part of a known attack campaign?

Yes — express-router-engine is associated with the IN-MAL-2026-009285, IN-MAL-2026-009322, IN-MAL-2026-009323 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 express-router-engine 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 express-router-engine (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging express-router-engine across your stack and pipelines.

Malicious package

express-router-enginenpm

Malicious code in express-router-engine (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-10063

Immediate action

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

npm uninstall express-router-engine

What this malware does

The sole shipped file index.js is a heavily obfuscated (RC4 + base64 string-array, 337-entry rotated array, control-flow flattening) IIFE that executes at require() time. On load it constructs a URL from encrypted string constants plus the package version, issues an HTTP GET with an Authentication header, splits the response body on ':' to derive a symmetric key and IV, decrypts the payload with crypto.createDecipheriv, writes the decrypted bytes to a file under a temp/home path, and executes that file via child_process.exec with windowsHide:true. All module names (fs, os, path, child_process, http client), the fetch URL, header name/value, crypto algorithm, and temp path components are stored encrypted in the string array — the obfuscation exists purely to hide the C2 URL and payload pipeline. The package name (express-router-engine) also mismatches its own description text (express-route-engine is a lightweight routing framework...), consistent with name-confusion against a legitimate routing helper. Any consumer that requires this package fetches and executes attacker-controlled code on the installer's machine.

Malicious versions

3 flagged

3.6.53.6.63.6.7

Indicators of compromise (SHA-256)

49091d8e8923e3e709cebd14f01ee1617267bf3f9b6be99052603715b7cf9f70

8ccf7c2321da04d59215e49cc91b2dc6da1cc66606ff968d968f397286f1ed3c

f8a4b520ba7169b1a71e922c24e8b5f70d7c5205b0c21b808fda327d907f0fe4

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for express-router-engine (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging express-router-engine across your stack and pipelines.
If you installed it — respond
express-router-engine 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 express-router-engine 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 express-router-engine 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. express-router-engine on npm has been identified as a malicious package (versions 3.6.5, 3.6.6, 3.6.7 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-009285IN-MAL-2026-009322IN-MAL-2026-009323

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks express-router-engine-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