Detect Inhibit System Recovery in CrowdStrike LogScale
Adversaries may delete or remove built-in data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery. This includes deleting Volume Shadow Copies (VSS), disabling Windows Recovery Environment (WinRE), clearing backup catalogs, and modifying Boot Configuration Data (BCD). This technique is almost universally observed as a pre-encryption step in ransomware attacks, executed within seconds to minutes before the encryption payload is launched. Real-world ransomware families including Ryuk, Black Basta, Medusa, RobbinHood, WastedLocker, EKANS, and Ragnar Locker all employ this technique to maximize the irreversibility of damage.
MITRE ATT&CK
- Tactic
- Impact
- Technique
- T1490 Inhibit System Recovery
- Canonical reference
- https://attack.mitre.org/techniques/T1490/
LogScale Detection Query
#event_simpleName=ProcessRollup2
| FileName = /(?i)(vssadmin|wmic|diskshadow|wbadmin|bcdedit|reagentc)\.exe/
| CommandLine = /(?i)(delete\s+shadows|delete\s+shadow\s|shadowcopy\s+delete|delete\s+catalog|resize\s+shadowstorage|recoveryenabled|bootstatuspolicy|safeboot|\/disable|-disable)/
| TechniqueCategory := case {
CommandLine = /(?i)(delete\s+shadows|shadowcopy\s+delete)/ => "VSS_Delete" ;
CommandLine = /(?i)delete\s+catalog/ => "BackupCatalog_Delete" ;
CommandLine = /(?i)resize\s+shadowstorage/ => "VSS_Resize" ;
CommandLine = /(?i)(recoveryenabled|bootstatuspolicy|safeboot)/ => "BCD_Recovery_Disable" ;
FileName = /(?i)reagentc\.exe/ AND CommandLine = /(?i)(disable)/ => "WinRE_Disable" ;
* => "Other_Recovery_Inhibit"
}
| table([timestamp, ComputerName, UserName, FileName, CommandLine, ParentBaseFileName, TechniqueCategory])
| sort(timestamp, order=desc)CrowdStrike LogScale (Falcon) query detecting T1490 Inhibit System Recovery using ProcessRollup2 sensor events from endpoints with the Falcon sensor deployed. Matches the known recovery inhibition binary set executing with command-line arguments for VSS deletion, backup catalog removal, shadow storage resizing, BCD modification, and WinRE disabling. Results are tagged with a TechniqueCategory field for triage prioritization.
Data Sources
Required Tables
False Positives & Tuning
- Veeam, Acronis, or other enterprise backup agents running under designated service accounts that invoke vssadmin or wbadmin to manage snapshot storage as part of automated backup schedules
- Windows operating system in-place upgrade processes (Windows Setup) that temporarily disable WinRE or modify BCD configuration entries during major OS version upgrades
- Storage capacity management automation scripts executed by infrastructure teams to resize shadow copy storage allocations on high-throughput file servers or database hosts
Other platforms for T1490
Testing Methodology
Validate this detection against 5 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1VSS Shadow Copy Deletion via vssadmin
Expected signal: Sysmon Event ID 1: Process Create with Image=vssadmin.exe, CommandLine='vssadmin.exe delete shadows /all /quiet'. Security Event ID 4688 (if command line auditing enabled) with same details. Microsoft-Windows-Volume-Shadow-Copy/Operational Event ID 8194 on deletion attempt.
- Test 2VSS Shadow Copy Deletion via WMI
Expected signal: Sysmon Event ID 1: Process Create with Image=wmic.exe, CommandLine='wmic shadowcopy delete'. Security Event ID 4688 with same details. WMI activity logs in Microsoft-Windows-WMI-Activity/Operational.
- Test 3Boot Recovery Disable via bcdedit
Expected signal: Two Sysmon Event ID 1 events: first with CommandLine='bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures', second with CommandLine='bcdedit.exe /set {default} recoveryenabled no'. Security Event ID 4688 for each. Both events fire within milliseconds of each other from the same parent.
- Test 4Windows Backup Catalog Deletion via wbadmin
Expected signal: Sysmon Event ID 1: Process Create with Image=wbadmin.exe, CommandLine='wbadmin.exe delete catalog -quiet'. Security Event ID 4688 with same details. Microsoft-Windows-Backup event log will record the catalog deletion operation.
- Test 5Ryuk-style VSS Storage Resize to Force Deletion
Expected signal: Sysmon Event ID 1: Process Create with Image=vssadmin.exe, CommandLine containing 'resize shadowstorage' and '/maxsize=401MB'. Microsoft-Windows-Volume-Shadow-Copy/Operational events as Windows responds to the reduced quota by discarding existing shadow copies.
References (10)
- https://attack.mitre.org/techniques/T1490/
- https://blog.talosintelligence.com/2018/02/olympic-destroyer.html
- https://www.fireeye.com/blog/threat-research/2017/05/wannacry-malware-profile.html
- https://www.cybereason.com/blog/cybereason-vs.-blackcat-ransomware
- https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/diskshadow
- https://www.zscaler.com/blogs/security-research/technical-analysis-crytox-ransomware
- https://rhinosecuritylabs.com/aws/s3-ransomware-part-2-prevention-and-defense/
- https://www.zdnet.com/article/ransomware-victims-thought-their-backups-were-safe-they-were-wrong/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1490/T1490.md
- https://github.com/SigmaHQ/sigma/tree/master/rules/windows/process_creation
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