Which versions of @krentzen/buffer-reverse are malicious?

The following npm versions of @krentzen/buffer-reverse are flagged malicious: 1.0.3. Treat any of these as compromised.

How do I remediate @krentzen/buffer-reverse if I installed it?

@krentzen/buffer-reverse is a typosquat — you almost certainly intended a legitimately-named package. Remove @krentzen/buffer-reverse, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed @krentzen/buffer-reverse — how do I know if it already compromised me?

If @krentzen/buffer-reverse 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.

Is @krentzen/buffer-reverse part of a known attack campaign?

Yes — @krentzen/buffer-reverse is associated with the IN-MAL-2026-007661 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find @krentzen/buffer-reverse across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @krentzen/buffer-reverse (version 1.0.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @krentzen/buffer-reverse across your stack and pipelines.

Malicious package

@krentzen/buffer-reversenpm

Malicious code in @krentzen/buffer-reverse (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-6536

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall @krentzen/buffer-reverse

What this malware does

@krentzen/buffer-reverse impersonates the well-known buffer-reverse package (it copies the legitimate author, repo URL, README, and the genuine ~10-line reverse() function at the top of index.js as a cover story). Below that cover, index.js contains two ~46KB heavily obfuscated IIFEs (RC4 string-array decoder, anti-debug, control-flow flattening) that run at require() time. The decoded payload performs an import-time binary dropper sequence: it re-spawns the current Node process with child_process.spawn(process.execPath, argv, {detached:true, stdio:'ignore', env:{...process.env, <marker>:set}}).unref() and returns in the parent (detaches from the consumer / npm install), then in the child issues an HTTPS GET (port 443) with full redirect handling (301/302/303/307/308), streams the response into a file under os.tmpdir(), writes a <file>.json sidecar containing {status, size, sha256, downloadedAt}, fs.chmodSync(file, 0o755), and child_process.spawn(file, [], {detached:true, stdio:'ignore', windowsHide:true}).unref(). The fetched binary is unpinned, unsigned, and has no publisher tie-in. Any project that require()s this package executes attacker-controlled native code that survives the parent process.

Malicious versions

1 flagged

1.0.3

Indicators of compromise (SHA-256)

7b7fccd6dbb7ba8a92be0bcbb002f92c43ff0c5e4bb82666589834a7be69e6bf

Detection & response playbook

Typosquat

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @krentzen/buffer-reverse (version 1.0.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @krentzen/buffer-reverse across your stack and pipelines.
If you installed it — respond
@krentzen/buffer-reverse is a typosquat — you almost certainly intended a legitimately-named package. Remove @krentzen/buffer-reverse, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If @krentzen/buffer-reverse 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 @krentzen/buffer-reverse 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

No. @krentzen/buffer-reverse on npm has been identified as a malicious package (version 1.0.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-007661

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks @krentzen/buffer-reverse-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.

Malware detection Runtime egress monitoring