Disk Content Wipe
Adversaries may erase the contents of storage devices on specific systems as well as large numbers of systems in a network to interrupt availability to system and network resources.
Adversaries may partially or completely overwrite the contents of a storage device rendering the data irrecoverable through the storage interface. Instead of wiping specific disk structures or files, adversaries with destructive intent may wipe arbitrary portions of disk content. To wipe disk content, adversaries may acquire direct access to the hard drive in order to overwrite arbitrarily sized portions of disk with random data. Adversaries have been observed leveraging third-party drivers like RawDisk to directly access disk content. This behavior is distinct from Data Destruction because sections of the disk erased instead of individual files.
To maximize impact on the target organization in operations where network-wide availability interruption is the goal, malware used for wiping disk content may have worm-like features to propagate across a network by leveraging additional techniques like Valid Accounts, Credential Dumping, and Windows Admin Shares.
Lazarus Group has used malware like WhiskeyAlfa to overwrite the first 64MB of every drive with a mix of static and random buffers. A similar process is then used to wipe content in logical drives and, finally, attempt to wipe every byte of every sector on every drive. WhiskeyBravo can be used to overwrite the first 4.9MB of physical drives. WhiskeyDelta can overwrite the first 132MB or 1.5MB of each drive with random data from heap memory.
Consider implementing IT disaster recovery plans that contain procedures for taking regular data backups that can be used to restore organizational data. Ensure backups are stored off system and is protected from common methods adversaries may use to gain access and destroy the backups to prevent recovery.
Look for attempts to read/write to sensitive locations like the partition boot sector or BIOS parameter block/superblock. Monitor for unusual kernel driver installation activity.
- Department of Justice. (2018, September 6). Criminal Complaint - United States of America v. PARK JIN HYOK. Retrieved March 29, 2019.
- Security Response attack Investigation Team. (2019, March 27). Elfin: Relentless Espionage Group Targets Multiple Organizations in Saudi Arabia and U.S.. Retrieved April 10, 2019.