Malicious Windows Boot Manager Backup Created by UEFI Bootkit
- Product
- windows
- Category
- file_event
- Author
- HuntRule
- Published
- 2026-09-23
- Updated
- 2026-09-23
ATT&CK techniques
Persistence → Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects creation of a bootmgfw.efi.old file on the EFI system partition, an artifact left when HybridPetya backs up the legitimate Windows Boot Manager before overwriting it with a malicious bootkit. Preserving the original boot manager under a .old name while hijacking the boot chain indicates pre-OS persistence and boot process tampering.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
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Also included
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