Unsigned Image Loaded Into LSASS Process

Status: test
Severity: medium
Log source: category image_load, product windows
Author: Teymur Kheirkhabarov, oscd.community
Source: github.com/SigmaHQ/sigma

Loading unsigned image (DLL, EXE) into LSASS process

Known false positives

Valid user connecting using RDP

MITRE ATT&CK coverage

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

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 7: Image loaded

Rule body

title: Unsigned Image Loaded Into LSASS Process
id: 857c8db3-c89b-42fb-882b-f681c7cf4da2
status: test
description: Loading unsigned image (DLL, EXE) into LSASS process
references:
    - https://www.slideshare.net/heirhabarov/hunting-for-credentials-dumping-in-windows-environment
author: Teymur Kheirkhabarov, oscd.community
date: 2019-10-22
modified: 2021-11-27
tags:
    - attack.credential-access
    - attack.t1003.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith: '\lsass.exe'
        Signed: 'false'
    condition: selection
falsepositives:
    - Valid user connecting using RDP
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    Image|endswith: '\lsass.exe'
    Signed: 'false'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\lsass.exe` corpus 5 (sigma 5)	`field:"Image" kind:ends_with value:"\lsass.exe"`
`Signed`	eq	`false` corpus 9 (splunk 5, sigma 4)	`field:"Signed" kind:eq value:"false"`

Unsigned Image Loaded Into LSASS Process

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`