An ISO file is a disk image: a single archive that can represent an entire CD, DVD, or virtual installer package. It is useful for legitimate software distribution because it preserves file structure and can be mounted like a real disc.
In cyber attacks, the same convenience makes ISO files attractive for hiding malware. A malicious ISO can contain scripts, installers, or shortcuts that look harmless until a user mounts the image and runs the embedded file. Because the file type often feels like a normal software package, it can bypass user suspicion in fake game builds, cracked software, and other lure-based downloads. Defenders should treat ISO files as executable-risk content, especially from unofficial sources, and scan them before opening. On endpoints, unexpected mount activity or child processes launched from a mounted image are useful warning signs.