bytefaas-sdknpm
Malicious code in bytefaas-sdk (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
Package published at version 9999.0.0 under the name bytefaas-sdk, the canonical dependency-confusion shape used to shadow a private internal package of the same name. package.json declares a preinstall hook that runs callback.js. On any npm install, callback.js collects the installer's os.hostname(), os.userInfo().username, platform, and cwd and transmits them to a third-party Interactsh (oast.fun) endpoint via both a DNS lookup (encoded subdomain) and an HTTPS POST. The HTTPS request sets rejectUnauthorized: false, disabling TLS certificate verification on the beacon. The package's README self-describes as a bug-bounty canary against TikTok's internal build systems, but the exfiltration fires unconditionally against any installer whose resolver picks up this public 9999.0.0 release — including unrelated organizations and CI systems. Cover-story framing does not change that non-consenting installers' host identifiers leak to a third-party server.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for bytefaas-sdk (version 9999.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bytefaas-sdk across your stack and pipelines.
If you installed it — respond
bytefaas-sdk is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If bytefaas-sdk 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 bytefaas-sdk 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 bytefaas-sdk-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.