LWA-2026-10833 confirmed malware

@ethers-js/contracts@6.9.0

Malicious code in @ethers-js/contracts (npm)

T1059.007 · JavaScriptT1059.003 · Windows Command ShellT1059.006 · PythonT1105 · Ingress Tool TransferT1195.002 · Compromise Software Supply Chain

Analysis

The postinstall hook (scripts/postinstall.js) is a Windows-targeted downloader. On win32 only, it creates a hidden directory under LOCALAPPDATA/TEMP named 'Microsoft/<random>', downloads a ZIP from hxxps://marxl[.]com/bin/wvt/swat/7aX0ci[.]zip, extracts it with powershell (Expand-Archive), then launches pythonw.exe r.py from the extracted contents as a detached background process and deletes the ZIP. The package name impersonates the ethers.js project.

analyzed by
Leitwacht
first seen
Aug 8, 2026, 11:37 AM
analyzed
Aug 8, 2026, 11:37 AM

Related advisories

browse all confirmed advisories →

Independently detected by the Leitwacht supply-chain probe. IOCs are defanged. Published CC0. Think this is a mistake? See the dispute policy.