@secauditb20y/sec-test-r3bnpm
Advisory published Updated
@secauditb20y/sec-test-r3b is a confirmed malicious npm package (MAL-2026-13989) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @secauditb20y/sec-test-r3b (npm)
What this malware does
package.json declares a postinstall script that runs node -e to invoke fs.writeFileSync, creating /tmp/PWN_R3REAL/FIRED on the installer's machine when the package is installed. The package's main module only exports the literal value 42 and ships no native build or legitimate reason for install-time execution; the postinstall exists solely to demonstrate arbitrary code execution on the installer host at npm install time. The behavior fires automatically on default install and writes to a path outside the package directory, matching the shape of a proof-of-execution beacon. The package name and description self-identify as an authorized security test, but self-labeling is not a mitigation and the code path is functionally identical to a dropper marker.
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
Search your lockfiles and build artifacts for @secauditb20y/sec-test-r3b (version 1.0.0).
If you installed it — respond
@secauditb20y/sec-test-r3b 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 @secauditb20y/sec-test-r3b was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks @secauditb20y/sec-test-r3b-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.