datefmt-helpernpm
datefmt-helper is a confirmed malicious npm package (MAL-2026-6788) that typosquats a legitimate package to trick installs (malicious versions 1.0.0, 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in datefmt-helper (npm)
What this malware does
The npm package datefmt-helper is a supply-chain dropper disguised as a benign date-formatting utility (its description reads "dates formatting utility with locale support"). The package ships no source repository and places its real behaviour in an install script.
A postinstall lifecycle hook (postinstall: node postinstall.js) executes automatically on npm install, before the package is ever imported. The install script uses HTTP / curl / wget primitives to download a second-stage payload from the hardcoded external IP 115.190.124.243, then executes it via a Node child process — the classic download-and-execute pattern. Any developer workstation or CI runner that installs the package (directly or transitively) hands arbitrary code execution to the operator of that endpoint.
Detected and classified independently by codelake Research from the live npm feed on 2026-07-02; at the time of reporting the package was not present in OSV or GHSA (a first-catch).
On npm install, the package's postinstall script fetches an unauthenticated payload over plain HTTP from a hardcoded bare IP (115.190.124.243:8761) and executes it. On Unix, curl/wget output is piped directly to sh. On Windows, certutil.exe -urlcache -split -f downloads a batch file to C:\Users\Public\run.bat and executes it. The fetched content is unpinned, unverified, and mutable — the operator of the endpoint can serve arbitrary code at any time. The package advertises itself as a lightweight date formatter (date-fns-lite branding, impersonating the date-fns ecosystem), but the payload has no relationship to date formatting. The typosquat/impersonation branding combined with an install-time dropper is a supply-chain attack lure.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for datefmt-helper (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging datefmt-helper across your stack and pipelines.
If you installed it — respond
datefmt-helper is a typosquat — you almost certainly intended a legitimately-named package. Remove datefmt-helper, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If datefmt-helper 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 datefmt-helper 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
Campaign
References
Credits
- Amazon Inspector · finder
- codelake Research · finder
Detect & block this
O3 blocks datefmt-helper-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.