claims-to-iso-string-with-timezonenpm
claims-to-iso-string-with-timezone is a confirmed malicious npm package (MAL-2026-12644) that typosquats a legitimate package to trick installs (malicious version 35.7.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in claims-to-iso-string-with-timezone (npm)
What this malware does
On require of claims-to-iso-string-with-timezone, index.js loads./init.js which downloads a platform-specific binary from obfuscated author-controlled endpoints (Cloudflare Workers hostnames oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev with a DNS-TXT fallback to sdk.dl.wel1.ru) reconstructed from string-array joins, writes it to /tmp/.cache<rand> or %TEMP%\dotnet_diag_<rnd>.exe, chmods it 0755, and spawns it detached via cp.spawn("/bin/sh", ["-c", fp + " &"]) or spawn("cmd",...). The package advertises itself as a date/timezone formatting utility with no declared dependencies; the dropper require is wrapped in a try/catch to swallow errors, and the dropped binary is named to impersonate dotnet diagnostic tooling. The package name resembles a legitimate date-formatting utility, and the harmful behavior is isolated in _init.js loaded by index.js.
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 claims-to-iso-string-with-timezone (version 35.7.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claims-to-iso-string-with-timezone across your stack and pipelines.
If you installed it — respond
claims-to-iso-string-with-timezone is a typosquat — you almost certainly intended a legitimately-named package. Remove claims-to-iso-string-with-timezone, 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 claims-to-iso-string-with-timezone 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 claims-to-iso-string-with-timezone 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 claims-to-iso-string-with-timezone-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.