{
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	"created_at": "2026-04-06T00:09:46.807507Z",
	"updated_at": "2026-04-10T03:21:14.977268Z",
	"deleted_at": null,
	"sha1_hash": "1e5aed87c724860194ecd6fc2dcf0cdc5b0d543d",
	"title": "New RegretLocker ransomware targets Windows virtual machines",
	"llm_title": "",
	"authors": "",
	"file_creation_date": "0001-01-01T00:00:00Z",
	"file_modification_date": "0001-01-01T00:00:00Z",
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	"plain_text": "New RegretLocker ransomware targets Windows virtual machines\r\nBy Lawrence Abrams\r\nPublished: 2020-11-03 · Archived: 2026-04-05 20:06:14 UTC\r\nA new ransomware called RegretLocker uses a variety of advanced features that allows it to encrypt virtual hard drives and\r\nclose open files for encryption.\r\nRegretLocker was discovered in October and is a simple ransomware in terms of appearance as it does not contain a long-winded ransom note and uses email for communication rather than a Tor payment site.\r\nRegretLocker ransom note\r\nSource: BleepingComputer\r\nWhen encrypting files, it will append the innocuous-sounding .mouse extension to encrypted file names.\r\nhttps://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nPage 1 of 6\n\n0:00\r\nhttps://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nPage 2 of 6\n\nVisit Advertiser websiteGO TO PAGE\r\nRegretLocker encrypted files\r\nSource: BleepingComputer\r\nWhat it lacks in appearance, though, it makes up for in advanced features that we do not usually see in ransomware\r\ninfections, as described below.\r\nRegretLocker mounts virtual hard disks\r\nWhen creating a Windows Hyper-V virtual machine, a virtual hard disk is created and stored in a VHD or VHDX file.\r\nThese virtual hard disk files contain a raw disk image, including a drive's partition table and partitions, and like regular disk\r\ndrives, can range in size from a few gigabytes to terabytes.\r\nWhen a ransomware encrypts files on a computer, it is not efficient to encrypt a large file as it slows down the entire\r\nencryption process's speed.\r\nIn a sample of the ransomware discovered by MalwareHunterTeam and analyzed by Advanced Intel's Vitali Kremez,\r\nRegretLocker uses an interesting technique of mounting a virtual disk file so each of its files can be encrypted individually.\r\nTo do this, RegretLocker uses the Windows Virtual Storage API OpenVirtualDisk, AttachVirtualDisk, and\r\nGetVirtualDiskPhysicalPath functions to mount virtual disks.\r\nhttps://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nPage 3 of 6\n\nMounting a VHD file\r\nAs shown by a debug message in the ransomware, it is specifically searching for VHD and mounting them when detected.\r\nparse_files() | Found virtual drive: %ws in path: %s\r\nOnce the virtual drive is mounted as a physical disk in Windows, the ransomware can encrypt each one individually, which\r\nincreases the speed of encryption.\r\nThe code used by RegretLocker to mount a VHD is believed to have been taken from a recently published research by\r\nsecurity researcher smelly__vx.\r\nIn addition to using the Virtual Storage API, RegretLocker also utilizes the Windows Restart Manager API to terminate\r\nprocesses or Windows services that keep a file open during encryption.\r\nWhen using this API, Kremez told BleepingComputer if the name of a process contains 'vnc', 'ssh', 'mstsc', 'System', or\r\n'svchost.exe', the ransomware will not terminate it. This exception list is likely used to prevent the termination of critical\r\nprograms or those used by the threat actor to access the compromised system.\r\nhttps://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nPage 4 of 6\n\nWindows Restart Manager exception list\r\nThe Windows Restart Manager feature is only used by a few ransomware such as REvil (Sodinokibi),\r\nRyuk, Conti, ThunderX/Ako, Medusa Locker, SamSam, and LockerGoga.\r\nRegretLocker is not very active at this point, but it is a new family that we need to keep an eye on.\r\nhttps://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nPage 5 of 6\n\nAutomated Pentesting Covers Only 1 of 6 Surfaces.\r\nAutomated pentesting proves the path exists. BAS proves whether your controls stop it. Most teams run one without the\r\nother.\r\nThis whitepaper maps six validation surfaces, shows where coverage ends, and provides practitioners with three diagnostic\r\nquestions for any tool evaluation.\r\nSource: https://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nhttps://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/\r\nPage 6 of 6",
	"extraction_quality": 1,
	"language": "EN",
	"sources": [
		"Malpedia"
	],
	"references": [
		"https://www.bleepingcomputer.com/news/security/new-regretlocker-ransomware-targets-windows-virtual-machines/"
	],
	"report_names": [
		"new-regretlocker-ransomware-targets-windows-virtual-machines"
	],
	"threat_actors": [],
	"ts_created_at": 1775434186,
	"ts_updated_at": 1775791274,
	"ts_creation_date": 0,
	"ts_modification_date": 0,
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