chalk-libnpm
chalk-lib is a confirmed malicious npm package (MAL-2026-14167) that typosquats a legitimate package to trick installs (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in chalk-lib (npm)
What this malware does
chalk-lib is a typosquat of the popular chalk package with an empty library body (index.js exports {}) whose entire effect is the postinstall lifecycle script. On npm install, scripts/postinstall.js XOR-decodes (key 'stf2026') a hardcoded URL pointing at github.com/bebraz1/qPzM50V1AKG0rVlH/releases/download/null/main.exe, downloads the executable to %TEMP%/main.exe on Windows, and spawns it detached with stdio:'ignore' and windowsHide:true. When the environment is WSL or Linux with the Windows host reachable (WSL_DISTRO_NAME / /proc/version / /proc/sys/kernel/osrelease containing 'microsoft'), a second code path XOR-decodes a PowerShell bridge command and script and exec()s it to fetch and run the same binary on the Windows host, extending the attack across the WSL boundary. In parallel, postinstall POSTs a JSON body containing the installer's platform label to a hardcoded bare-IP endpoint at 193.70.34.101:20099/vote over plain HTTP; the IP is assembled by joining the octet array ['193','70','34','101'] to evade static string matching. URLs, the PowerShell command, and the bridge script are all stored as integer arrays and reconstructed via an XOR unpackSegment() routine.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Search your lockfiles and build artifacts for chalk-lib (version 1.0.0).
If you installed it — respond
chalk-lib is a typosquat — you almost certainly intended a legitimately-named package. Remove chalk-lib, 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 chalk-lib 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 chalk-lib-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.