Greenshot Vulnerable to OS Command Injection via ExternalCommand Plugin

Summary

Greenshot is an open source Windows screenshot utility. Versions 1.3.312 and below have untrusted executable search path / binary hijacking vulnerability that allows a local attacker to execute arbitrary code when the affected Windows application launches explorer.exe without using an absolute path. The vulnerable behavior is triggered when the user double-clicks the application’s tray icon, which opens the directory containing the most recent screenshot captured by the application. By placing a malicious executable with the same name in a location searched prior to the legitimate Windows binary, an attacker can gain code execution in the context of the application. This issue did not have a patch at the time of publication.