LSASS dump via process access

Status: experimental
Severity: high
Log source: category process_access, product windows
Author: mdecrevoisier
Source: github.com/mdecrevoisier/SIGMA-detection-rules

Detects scenarios where an attacker attempt to dump LSASS process with tools like Mimikatz.

Known false positives

Antivirus, security products, browsers

MITRE ATT&CK coverage

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

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 10: ProcessAccess

Rule body

title: LSASS dump via process access
description: Detects scenarios where an attacker attempt to dump LSASS process with tools like Mimikatz.
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0006-Credential%20Access/T1003-Credential%20dumping
- https://threathunterplaybook.com/notebooks/windows/06_credential_access/WIN-191030201010.html
- https://medium.com/threatpunter/detecting-attempts-to-steal-passwords-from-memory-558f16dce4ea
- https://cyberwardog.blogspot.com/2017/03/chronicles-of-threat-hunter-hunting-for_22.html
tags:
- attack.credential_access
- attack.t1003.001
author: mdecrevoisier
status: experimental
logsource:
  product: windows
  category: process_access
detection:
  selection:
    EventID: 10 # process accessed
    TargetImage|endswith: '\system32\lsass.exe'
    GrantedAccess:
      - '0x1410'
      - '0x1010'
      - '0x1438' # could refers to misc::memssp
      - '0x143a'
      - '0x1418'
      - '0x1fffff' # ProcDump
  filter:
    SourceImage:
      - '*\ProgramData\Microsoft\Windows Defender\Platform\*'
      - '*\Program Files\Windows Defender Advanced Threat Protection\*'
      - '*\system32\csrss.exe'
      - '*\system32\wininit.exe'
  condition: selection and not filter
falsepositives:
- Antivirus, security products, browsers
level: high

Stages and Predicates

Stage 0: `condition`

selection and not filter

Stage 1: `selection`

selection:
  EventID: 10
  TargetImage|endswith: '\system32\lsass.exe'
  GrantedAccess:
    - '0x1410'
    - '0x1010'
    - '0x1438'
    - '0x143a'
    - '0x1418'
    - '0x1fffff'

Stage 2: `not filter`

filter:
  SourceImage:
    - '*\ProgramData\Microsoft\Windows Defender\Platform\*'
    - '*\Program Files\Windows Defender Advanced Threat Protection\*'
    - '*\system32\csrss.exe'
    - '*\system32\wininit.exe'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`SourceImage`	ends_with	`\system32\csrss.exe`	`excludes:SourceImage` `field:"SourceImage" value:"\system32\csrss.exe"`
`SourceImage`	ends_with	`\system32\wininit.exe`	`excludes:SourceImage` `field:"SourceImage" value:"\system32\wininit.exe"`
`SourceImage`	match	`\Program Files\Windows Defender Advanced Threat Protection\`	`excludes:SourceImage` `field:"SourceImage" value:"\Program Files\Windows Defender Advanced Threat Protection\"`
`SourceImage`	match	`\ProgramData\Microsoft\Windows Defender\Platform\`	`excludes:SourceImage` `field:"SourceImage" value:"\ProgramData\Microsoft\Windows Defender\Platform\"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`GrantedAccess`	eq	`0x1010` corpus 2 (sigma 1, splunk 1) `0x1410` corpus 2 (sigma 1, splunk 1) `0x1418` `0x1438` `0x143a` corpus 2 (sigma 2) `0x1fffff` corpus 9 (sigma 7, splunk 1, kusto 1)	`field:"GrantedAccess" kind:eq`
`TargetImage`	ends_with	`\system32\lsass.exe`	`field:"TargetImage" kind:ends_with value:"\system32\lsass.exe"`

LSASS dump via process access

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter`