Backup Files Deleted

Severity: medium
Author: frack113
Source: upstream

Detects deletion of files with extensions often used for backup files. Adversaries may delete or remove built-in operating system data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery.

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1490` Inhibit System Recovery

Event coverage

Provider	Event ID	Title
Sysmon	23	FileDelete (File Delete archived)
Sysmon	26	FileDeleteDetected (File Delete logged)

Stages and Predicates

Stage 1: `selection`

or:
Image|endswith: '\cmd.exe'
Image|endswith: '\powershell.exe'
Image|endswith: '\pwsh.exe'
Image|endswith: '\regsvr32.exe'
Image|endswith: '\rundll32.exe'
Image|endswith: '\wt.exe'
or:
TargetFilename|endswith: .VHD
TargetFilename|endswith: .bac
TargetFilename|endswith: .bak
TargetFilename|endswith: .bkf
TargetFilename|endswith: .dsk
TargetFilename|endswith: .set
TargetFilename|endswith: .wbcat
TargetFilename|endswith: .win

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.