Which versions of caspian-day-js are malicious?

The following npm versions of caspian-day-js are flagged malicious: 1.11.23. Treat any of these as compromised.

How do I remediate caspian-day-js if I installed it?

caspian-day-js 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.

I already installed caspian-day-js — how do I know if it already compromised me?

If caspian-day-js 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.

Is caspian-day-js part of a known attack campaign?

Yes — caspian-day-js is associated with the IN-MAL-2026-006769 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find caspian-day-js across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for caspian-day-js (version 1.11.23). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging caspian-day-js across your stack and pipelines.

Malicious package

caspian-day-jsnpm

caspian-day-js is a confirmed malicious npm package (MAL-2026-5892) that opens a backdoor for remote access (malicious version 1.11.23). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in caspian-day-js (npm)

MAL-2026-5892

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall caspian-day-js

What this malware does

caspian-day-js impersonates the popular dayjs package: package.json copies author iamkun, homepage day.js.org, and repo github.com/iamkun/dayjs.git, and ships an unmodified dayjs.min.js as main so require('caspian-day-js') appears functional. The malicious payload is in the lifecycle hook: package.json declares postinstall: node setup.cjs. setup.cjs is heavily obfuscated (obfuscator.io-style string-array with a custom base64 decoder) and at install time sets NODE_TLS_REJECT_UNAUTHORIZED='0', fetches a remote JavaScript payload, writes it to <tmpdir>/<12-hex>.js, then spawns process.execPath on the dropped file (detached, stdio:'ignore', windowsHide:true) with the C2 endpoint 23.254.164.123:443 passed as argv[1], and finally unlinks setup.cjs to erase traces. Every machine running npm install caspian-day-js executes attacker-controlled JavaScript with TLS verification disabled, contacting 23.254.164.123:443.

Malicious versions

1 flagged

1.11.23

Indicators of compromise (SHA-256)

895fe8e087ec7af36d61e8a6972f484e70bc1b828374ae83cef9ff4a927f7b55

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for caspian-day-js (version 1.11.23). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging caspian-day-js across your stack and pipelines.
If you installed it — respond
caspian-day-js 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 caspian-day-js 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 caspian-day-js 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

No. caspian-day-js on npm has been identified as a malicious package (version 1.11.23 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-006769

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks caspian-day-js-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

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