Potential MsiExec Masquerading

Severity: high
Author: Florian Roth (Nextron Systems)
Source: upstream

Detects the execution of msiexec.exe from an uncommon directory

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1036.005` Masquerading: Match Legitimate Resource Name or Location

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `selection`

or:
Image|endswith: '\msiexec.exe'
OriginalFileName: '\msiexec.exe'

Stage 2: `not filter`

or:
Image|startswith: 'C:\Windows\SysWOW64\'
Image|startswith: 'C:\Windows\System32\'
Image|startswith: 'C:\Windows\WinSxS\'

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
`Image`	ends_with	`\msiexec.exe` corpus 21 (sigma 21)
`Image`	starts_with	`C:\Windows\SysWOW64\` corpus 16 (sigma 16) `C:\Windows\System32\` corpus 16 (sigma 16) `C:\Windows\WinSxS\` corpus 13 (sigma 13)
`OriginalFileName`	eq	`\msiexec.exe` corpus 2 (sigma 2)