@bcryptln/becryptjsnpm
Malicious code in @bcryptln/becryptjs (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
Package @bcryptln/becryptjs impersonates the widely-used bcryptjs library (its own metadata still references the upstream dcodeIO/bcrypt.js project). The ESM entrypoint index.js contains a legitimate copy of bcryptjs followed by whitespace padding and an appended obfuscated block that runs unconditionally when a consumer does import '@bcryptln/becryptjs'. The trailing code hoists require, module, __dirname, and __filename onto globals, then uses two custom positional string-shuffle decoders with hardcoded numeric seeds to derive the identifier Function, constructs a runtime function from a decoded string, and invokes it. Because require is re-exposed to the constructed function, the payload has full CommonJS reach (fs, child_process, http, net) from within an ESM module. The CommonJS/UMD entrypoint (umd/index.js) is a clean copy of upstream with no payload — the malicious code is placed only on the import conditional export, targeting modern ESM consumers while keeping the require path benign to defeat diff-against-upstream review. The combination of name impersonation, hidden payload appended after whitespace padding, custom string-shuffle obfuscation whose only purpose is to hide Function and the payload body, dynamic code construction with re-exposed CommonJS primitives, and UMD/ESM split are jointly consistent with an intentional supply-chain trojan.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @bcryptln/becryptjs (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @bcryptln/becryptjs across your stack and pipelines.
If you installed it — respond
@bcryptln/becryptjs is a typosquat — you almost certainly intended a legitimately-named package. Remove @bcryptln/becryptjs, 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 @bcryptln/becryptjs 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 @bcryptln/becryptjs 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 @bcryptln/becryptjs-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.