WinRAR Execution in Non-Standard Folder

Severity: medium
Author: Florian Roth (Nextron Systems), Tigzy
Source: upstream

Detects a suspicious WinRAR execution in a folder which is not the default installation folder

MITRE ATT&CK coverage

Tactic	Techniques
Collection	`T1560.001` Archive Collected Data: Archive via Utility

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `selection`

or:
Description: 'Command line RAR'
Description: WinRAR
Image|endswith: '\rar.exe'
Image|endswith: '\winrar.exe'

Stage 2: `not 1 of filter_main_*`

or:
Image|endswith: '\UnRAR.exe'
Image|contains: ':\Program Files (x86)\WinRAR\'
Image|contains: ':\Program Files\WinRAR\'

Stage 3: `not 1 of filter_optional_temp`

Image|contains: ':\Windows\Temp\'

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.

Field	Kind	Values
`Description`	eq	`Command line RAR` corpus 3 (sigma 3) `WinRAR`
`Image`	ends_with	`\UnRAR.exe` `\rar.exe` corpus 4 (sigma 4) `\winrar.exe` corpus 2 (sigma 2)
`Image`	match	`:\Program Files (x86)\WinRAR\` `:\Program Files\WinRAR\` `:\Windows\Temp\` corpus 9 (sigma 9)