OpenSSF/OSV advisory MAL-2026-14143 confirms this npm version as malicious. tyepescript-cli is a typosquat of `typescript`. Its `scripts/postinstall.js` XOR-decodes (key `stf2026`) a set of obfuscated byte arrays that resolve to an attacker-controlled URL, a PowerShell bridge command, and script fragments. On Windows, the postinstall downloads `main.exe` from `github.com/bebrazi/qPbM50V1AKG0rVlH/releases/download/null/main.exe` to `%TEMP%\main.exe` and spawns it detached...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in tyepescript-cli (npm)
Details
tyepescript-cli is a typosquat of `typescript`. Its `scripts/postinstall.js` XOR-decodes (key `stf2026`) a set of obfuscated byte arrays that resolve to an attacker-controlled URL, a PowerShell bridge command, and script fragments. On Windows, the postinstall downloads `main.exe` from `github.com/bebrazi/qPbM50V1AKG0rVlH/releases/download/null/main.exe` to `%TEMP%\main.exe` and spawns it detached. Under WSL, it decodes a `powershell.exe` bridge command and execs it via `child_process.exec` with `windowsHide: true` to fetch and run the same binary on the Windows host from the Linux install context. Before the drop, the script POSTs a JSON body with a host label to a hardcoded numeric IP `http://193.70.34.101:20099/vote` (host built by joining the array `['193','70','34','101']` to hide the literal) as an install-time beacon. The mutable `releases/download/null/` path on an anonymous personal GitHub account (`bebrazi`) is unrelated to any legitimate `typescript` publisher, and the XOR obfuscation of URLs and commands has no benign purpose in an npm install script.
Decision reason
OpenSSF Malicious Packages via OSV confirms tyepescript-cli@1.0.0 as malicious (MAL-2026-14143): Malicious code in tyepescript-cli (npm)