datefmt-pronpm
Advisory published Updated
datefmt-pro is a confirmed malicious npm package (MAL-2026-12175) that opens a backdoor for remote access (malicious versions 1.0.0, 1.0.1, 1.0.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in datefmt-pro (npm)
What this malware does
datefmt-pro presents itself as a date formatting utility, but its actual behavior is an install-time reconnaissance beacon. The scripts.postinstall entry runs postinstall.js on npm install, which uses child_process.execSync to run hostname, whoami, uname -a, and pwd, and calls os.networkInterfaces() to enumerate non-internal IPv4 addresses. It then POSTs the collected identity and internal network information as JSON over plain HTTP to the hardcoded bare-IP endpoint http://129.204.76.212:9999/rce-poc. index.js contains only a trivial date-formatting stub whose in-source comments state it exists to make the package look like a real date library while the payload lives in postinstall.js. The package name imitates a plausible utility to attract installers via typo/trust; the advertised purpose does not require any host reconnaissance or outbound network activity at install time.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for datefmt-pro (3 malicious versions).
If you installed it — respond
datefmt-pro 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 datefmt-pro 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
Detect & block this
O3 blocks datefmt-pro-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.