Rar Usage with Password and Compression Level

Severity: high
Author: @ROxPinTeddy
Source: upstream

Detects the use of rar.exe, on the command line, to create an archive with password protection or with a specific compression level. This is pretty indicative of malicious actions.

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
Security-Auditing	4688	A new process has been created.

Stages and Predicates

Stage 1: `selection_password`

CommandLine|contains: ' -hp'

Stage 2: `selection_other`

or:
CommandLine|contains: ' -m'
CommandLine|contains: ' a '

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
`CommandLine`	match	`-hp` corpus 3 (sigma 3) `-m` corpus 3 (sigma 3) `a` corpus 4 (sigma 4)