Suspicious JavaScript Execution Via Mshta.EXE

Severity: high
Author: E.M. Anhaus (originally from Atomic Blue Detections, Endgame), oscd.community
Source: upstream

Detects execution of javascript code using "mshta.exe".

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1218.005` System Binary Proxy Execution: Mshta

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|endswith: '\mshta.exe'
OriginalFileName: MSHTA.EXE

Stage 2: `all of selection_cli`

CommandLine|contains: javascript

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	`javascript`
`Image`	ends_with	`\mshta.exe` corpus 57 (sigma 57)
`OriginalFileName`	eq	`MSHTA.EXE` corpus 7 (sigma 7)