@outmarket/utilsnpm
Advisory published Updated
@outmarket/utils is a confirmed malicious npm package (MAL-2026-6292) that opens a backdoor for remote access (malicious versions 9.9.9, 9.9.10, 9.9.11). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @outmarket/utils (npm)
What this malware does
package.json declares a postinstall lifecycle script that fires automatically on npm install. The inline node -e payload uses hex-encoded property names (\x6f\x73 for os, \x68\x6f\x73\x74\x6e\x61\x6d\x65 for hostname, \x75\x73\x65\x72\x49\x6e\x66\x6f for userInfo) to obscure that it reads os.hostname() and os.userInfo().username, then issues an HTTP GET to http://208.87.128.25:8888/?h=<hostname>&u=<username>. The destination is a bare IPv4 over cleartext HTTP — not a publisher domain or known infrastructure. The package is published under the @outmarket scope with a description identifying it as a dependency-confusion proof-of-concept, but the on-install behavior is indistinguishable from a real dependency-confusion beacon: any installer who resolves this public package in place of an internal @outmarket/utils will leak host identity to the hardcoded endpoint. Hex obfuscation of standard Node API names is evasion, not a legitimate engineering choice.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for @outmarket/utils (3 malicious versions).
If you installed it — respond
@outmarket/utils 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 @outmarket/utils 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
Campaign
References
Credits
- Amazon Inspector · finder
- ReversingLabs · finder
Detect & block this
O3 blocks @outmarket/utils-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.