File Download Via Windows Defender MpCmpRun.EXE

Severity: high
Author: Matthew Matchen
Source: upstream

Detects the use of Windows Defender MpCmdRun.EXE to download files

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1218` System Binary Proxy Execution
Command & Control	`T1105` Ingress Tool Transfer

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
CommandLine|contains: MpCmdRun.exe
Description: 'Microsoft Malware Protection Command Line Utility'
Image|endswith: '\MpCmdRun.exe'
OriginalFileName: MpCmdRun.exe

Stage 2: `all of selection_cli`

CommandLine|contains: DownloadFile
CommandLine|contains: url

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	`DownloadFile` corpus 2 (sigma 2) `MpCmdRun.exe` `url`
`Description`	eq	`Microsoft Malware Protection Command Line Utility`
`Image`	ends_with	`\MpCmdRun.exe` corpus 5 (sigma 5)
`OriginalFileName`	eq	`MpCmdRun.exe` corpus 2 (sigma 2)