An optical disk is a removable storage medium that holds data on a disc surface and is read by a laser, as in CDs, DVDs, and Blu-ray discs. Because the media is portable and often read-only once mastered, it can be useful for software distribution, backups, and archiving.
In cyber security, optical disks matter because removable media can carry both legitimate software and malicious payloads. Attackers may use discs to deliver malware, bypass network controls, or seed infected files into isolated systems that do not rely on downloads. Defenders respond with endpoint controls, malware scanning, disabled autorun features, and strict rules for using unknown media. Optical disks also appear in digital forensics, where investigators preserve and analyze disc images to track what was stored or executed on a system.