bytepack-probe-a7x3npm
bytepack-probe-a7x3 is a confirmed malicious npm package (MAL-2026-16364) that executes malicious code on install (malicious versions 1.0.0, 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in bytepack-probe-a7x3 (npm)
What this malware does
package.json declares a dependency leak-internal whose source is the HTTPS tarball URL https://src-ssrf.bytedance.net/ssrf/probe.tgz rather than a registry version range. On npm install, npm fetches and installs whatever bytes that URL currently returns, executing any lifecycle scripts contained in the fetched tarball. There is no version pin, no integrity hash, and no signature check, so the code executed on the installer's machine is whatever the operator of that host serves at the moment of install. The hostname suggests an SSRF-probe artifact hosted on an internal-looking domain, and the dependency name leak-internal together with the path segment ssrf/probe.tgz indicates the fetched payload is intended to run probing behavior inside the installer's network.
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 bytepack-probe-a7x3 (2 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging bytepack-probe-a7x3 across your stack and pipelines.
If you installed it — respond
Remove bytepack-probe-a7x3 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 bytepack-probe-a7x3 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 bytepack-probe-a7x3 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 bytepack-probe-a7x3-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.