Suspicious Renamed Comsvcs DLL Loaded By Rundll32

Severity: high
Author: Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects rundll32 loading a renamed comsvcs.dll to dump process memory

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1003.001` OS Credential Dumping: LSASS Memory

Event coverage

Provider	Event ID	Title
Sysmon	7	Image loaded

Stages and Predicates

Stage 1: `selection`

or:
Hashes|contains: 'IMPHASH=281d618f4e6271e527e6386ea6f748de'
Hashes|contains: 'IMPHASH=407ca0f7b523319d758a40d7c0193699'
Hashes|contains: 'IMPHASH=5e0dbdec1fce52daae251a110b4f309d'
Hashes|contains: 'IMPHASH=eadbccbb324829acb5f2bbe87e5549a8'
Hashes|contains: 'IMPHASH=eed93054cb555f3de70eaa9787f32ebb'
Image|endswith: '\rundll32.exe'

Stage 2: `not filter`

ImageLoaded|endswith: '\comsvcs.dll'

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
`Hashes`	match	`IMPHASH=281d618f4e6271e527e6386ea6f748de` `IMPHASH=407ca0f7b523319d758a40d7c0193699` `IMPHASH=5e0dbdec1fce52daae251a110b4f309d` `IMPHASH=eadbccbb324829acb5f2bbe87e5549a8` `IMPHASH=eed93054cb555f3de70eaa9787f32ebb`
`Image`	ends_with	`\rundll32.exe` corpus 76 (sigma 76)
`ImageLoaded`	ends_with	`\comsvcs.dll`