OpenSSF/OSV advisory MAL-2026-14156 confirms this npm version as malicious. typscript-cli is a typosquat of 'typescript' (index.js exports an empty object; no library functionality). Its scripts/postinstall.js is the only functional code and executes on npm install. It XOR-decodes (key 'stf2026') four embedded numeric arrays to reconstruct a download URL and a PowerShell 'bridge' command, downloads a Windows executable to %TEMP%\main.exe, and spawns it detached with windowsHide:true...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in typscript-cli (npm)
Details
typscript-cli is a typosquat of 'typescript' (index.js exports an empty object; no library functionality). Its scripts/postinstall.js is the only functional code and executes on npm install. It XOR-decodes (key 'stf2026') four embedded numeric arrays to reconstruct a download URL and a PowerShell 'bridge' command, downloads a Windows executable to %TEMP%\main.exe, and spawns it detached with windowsHide:true. On WSL/Linux hosts it uses child_process.exec with the XOR-decoded PowerShell bridge command to drop and run the same payload on the Windows side. The same postinstall also POSTs a platform label to a hardcoded bare-IP endpoint 193.70.34.101:20099/vote over plain HTTP, with the host assembled from a split array ['193','70','34','101'].join('.') to evade literal-string scanning. There is no publisher-matched destination, no version pinning, and no integrity check on the fetched binary.
Decision reason
OpenSSF Malicious Packages via OSV confirms typscript-cli@1.0.0 as malicious (MAL-2026-14156): Malicious code in typscript-cli (npm)