vybscan-testbed-obfuscated-postinstallnpm
Malicious code in vybscan-testbed-obfuscated-postinstall (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
package.json declares a postinstall lifecycle script that runs node -e "eval(Buffer.from('<base64>','base64').toString())". Installing the package triggers execution of code that is not visible in the package source and is only materialized at install time by decoding an opaque literal. In this specific version the decoded blob is an inert console.log, but the mechanism — obfuscated-then-eval'd bytes wired into a lifecycle hook — is the canonical install-time remote-code-execution shape and has no legitimate use: it lets whoever controls the package substitute arbitrary code at install without changing readable source. The package's self-description as a testbed fixture does not neutralize the pattern; the same install-time hook would execute whatever bytes were placed in the base64 literal.
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 vybscan-testbed-obfuscated-postinstall (version 1.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging vybscan-testbed-obfuscated-postinstall across your stack and pipelines.
If you installed it — respond
Remove vybscan-testbed-obfuscated-postinstall 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 vybscan-testbed-obfuscated-postinstall 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 vybscan-testbed-obfuscated-postinstall 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 vybscan-testbed-obfuscated-postinstall-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.