@finxsecdemo/utilsnpm
Advisory published Updated
@finxsecdemo/utils is a confirmed malicious npm package (MAL-2026-11170) that opens a backdoor for remote access (malicious versions 1.0.2, 1.0.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @finxsecdemo/utils (npm)
What this malware does
The postinstall.js lifecycle script unconditionally issues an HTTPS GET and a DNS resolution against a hardcoded interact.sh/OAST subdomain (llhvrrffsffmousfvteqie2heq3c7rl55.oast.fun) on every install, reading os.hostname(), os.userInfo(), and process.env in the surrounding code. The beacon fires on npm install and reports the installer's source IP and DNS resolver IP to whoever owns the OAST token, giving them an enumeration list of hosts on which the package landed. The package's own main returns a formatCurrency string containing '[DEPENDENCY-CONFUSION-POC: this ran from the PUBLIC npm registry, not @finxsecdemo private packages]', which corrupts any consumer that displays formatted currency. Console framing as a 'dependency confusion PoC' is author-controlled labeling; the network callback and output corruption occur regardless.
The OpenSSF Package Analysis project identified '@finxsecdemo/utils' @ 1.0.2 (npm) as malicious.
It is considered malicious because:
- The package communicates with a domain associated with malicious activity.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for @finxsecdemo/utils (2 malicious versions).
If you installed it — respond
@finxsecdemo/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 @finxsecdemo/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
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks @finxsecdemo/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.