client-cookies-agentnpm
client-cookies-agent is a confirmed malicious npm package (MAL-2026-10019) that opens a backdoor for remote access (malicious versions 99.9.5, 99.9.6, 99.9.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in client-cookies-agent (npm)
What this malware does
package.json declares postinstall=node index.js, which runs automatically on npm install. index.js collects host identifiers via os.hostname(), os.userInfo(), and process.cwd(), resolves the external IPv4 address, and POSTs them as JSON to a hardcoded Interactsh-style out-of-band collector at lpzlajzjfkpfeefuzxbv6n5nob7bpuh6e.oast.fun/receive-data over plain HTTP. The package has empty description and author fields and is published at version 99.9.5, a shape consistent with a dependency-confusion squat against a private/internal package name: installing (or accidentally resolving) this name causes a reconnaissance beacon to fire from the developer or CI machine, confirming code execution on the target and leaking host, user, cwd, and network identifiers to the attacker.
The OpenSSF Package Analysis project identified 'client-cookies-agent' @ 99.9.5 (npm) as malicious.
It is considered malicious because:
- The package communicates with a domain associated with malicious activity.
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 client-cookies-agent (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging client-cookies-agent across your stack and pipelines.
If you installed it — respond
client-cookies-agent 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 client-cookies-agent 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 client-cookies-agent 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 client-cookies-agent-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.