npm-show-date-proof-stringsnpm
npm-show-date-proof-strings is a confirmed malicious npm package (MAL-2026-6791) that opens a backdoor for remote access (malicious versions 1.0.3, 1.0.4). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in npm-show-date-proof-strings (npm)
What this malware does
The package's postinstall.js runs on every npm install and collects the installer's username (via whoami and os.userInfo()), hostname (os.hostname()), platform (process.platform), and Node version, then transmits them as query parameters via https.get() to a hardcoded endpoint at https://testnpm.byte.eyes.sh/npm-proof. The destination is author-controlled and undocumented; the installer has no opportunity to opt out. The package name ("npm-show-date-proof-strings") and an embedded NONCE string ("proof-2026-change-this-random-string") indicate this is a proof-of-execution beacon, but regardless of framing, it is unconsented host-identifier collection on install with no legitimate installer-facing purpose.
The OpenSSF Package Analysis project identified 'npm-show-date-proof-strings' @ 1.0.3 (npm) as malicious.
It is considered malicious because:
- The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for npm-show-date-proof-strings (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging npm-show-date-proof-strings across your stack and pipelines.
If you installed it — respond
npm-show-date-proof-strings 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 npm-show-date-proof-strings 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 npm-show-date-proof-strings 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
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks npm-show-date-proof-strings-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.