electron-builder's NSIS installer - execute arbitrary code on the target machine (Windows only)

Impact

Windows-Only: The NSIS installer makes a system call to open cmd.exe via NSExec in the .nsh installer script. NSExec by default searches the current directory of where the installer is located before searching PATH. This means that if an attacker can place a malicious executable file named cmd.exe in the same folder as the installer, the installer will run the malicious file.

Patches

Fixed in https://github.com/electron-userland/electron-builder/pull/8059

Workarounds

None, it executes at the installer-level before the app is present on the system, so there's no way to check if it exists in a current installer.

References

https://cwe.mitre.org/data/definitions/426.html
https://cwe.mitre.org/data/definitions/427