capacity-capacity-corenpm
capacity-capacity-core is a confirmed malicious npm package (MAL-2026-12522) that executes malicious code on install (malicious version 35.3.7). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in capacity-capacity-core (npm)
What this malware does
On require of the package's main entry, adapter.js downloads a platform-specific binary from one of three string-split-obfuscated Cloudflare Workers hosts (oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev), with a DNS TXT base64 fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under a disguised name (.cache<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmod 0755, and detach-spawned via /bin/sh -c 'fp &' or cmd.exe /c start. A mtime marker at /tmp/.analytics_state throttles re-execution. Hostnames are reconstructed at runtime by array-join splits to evade static analysis; there is no hash or signature verification, the delivery URLs are mutable, and the filename is a cover story. Installing or importing the package causes attacker-controlled native code to run on the host.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for capacity-capacity-core (version 35.3.7). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging capacity-capacity-core across your stack and pipelines.
If you installed it — respond
Remove capacity-capacity-core from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If capacity-capacity-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 capacity-capacity-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 capacity-capacity-core-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.