simple-date-formatter-util-13npm
simple-date-formatter-util-13 is a confirmed malicious npm package (MAL-2026-12202) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in simple-date-formatter-util-13 (npm)
What this malware does
Package presents itself as a date-formatting utility (index.js is a four-line toLocaleDateString wrapper) but its package.json postinstall hook runs an inline shell pipeline that reads /proc/self/status, /dev, /home/work, /wenchain, and /etc/hosts, probes internal Kubernetes API endpoints, and POSTs the collected output to an attacker-controlled Interactsh OAST endpoint at safjhdvsfwzhieemkdzbgr54r0yjhrmok.oast.fun/escinfo2. The tarball also ships postinstall.js, which enumerates the installer's ~/.ssh directory, gathers filenames plus username and platform, and POSTs the JSON payload over HTTPS to the hardcoded IP 124.221.154.135. Both behaviors auto-execute on npm install.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for simple-date-formatter-util-13 (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging simple-date-formatter-util-13 across your stack and pipelines.
If you installed it — respond
Remove simple-date-formatter-util-13 from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If simple-date-formatter-util-13 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 simple-date-formatter-util-13 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
Detect & block this
O3 blocks simple-date-formatter-util-13-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.