quartz-corenpm
quartz-core is a confirmed malicious npm package (MAL-2026-15671) that opens a backdoor for remote access (malicious versions 10.1.9, 99.1.9, 99.9.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in quartz-core (npm)
What this malware does
On npm install, the package's preinstall hook (package.json scripts.preinstall = node index.js) executes index.js, which reads the installer's OS username (os.userInfo().username), hostname (os.hostname()), and current working directory (process.cwd()), then issues a DNS A-record query for a subdomain of the attacker-controlled domain oob.algamil7x.xyz of the form selftest.<username>.<hostname>.<cwd>.<timestamp>.oob.algamil7x.xyz via dns.Resolver.resolve4. The tarball ships no other functionality: package.json has an empty description and author, no dependencies, and no runtime code beyond the beacon. The name quartz-core at the elevated version 99.1.9 is consistent with a dependency-confusion reconnaissance probe designed to identify internal build environments where a private package name resolves to this public one.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
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 quartz-core (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging quartz-core across your stack and pipelines.
If you installed it — respond
quartz-core 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 quartz-core 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 quartz-core 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 quartz-core-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.