Detection rules › Sigma

Uncommon Process Access Rights For Target Image

Status
test
Severity
low
Log source
category process_access, product windows
Author
Nasreddine Bencherchali (Nextron Systems), frack113
Source
github.com/SigmaHQ/sigma

Detects process access request to uncommon target images with a "PROCESS_ALL_ACCESS" access mask.

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 10: ProcessAccess

Rule body

title: Uncommon Process Access Rights For Target Image
id: a24e5861-c6ca-4fde-a93c-ba9256feddf0
status: test
description: |
    Detects process access request to uncommon target images with a "PROCESS_ALL_ACCESS" access mask.
references:
    - https://learn.microsoft.com/en-us/windows/win32/procthread/process-security-and-access-rights
author: Nasreddine Bencherchali (Nextron Systems), frack113
date: 2024-05-27
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055.011
logsource:
    category: process_access
    product: windows
detection:
    selection:
        TargetImage|endswith:
            # Note: Add additional uncommon targets to increase coverage.
            - '\calc.exe'
            - '\calculator.exe'
            - '\mspaint.exe'
            - '\notepad.exe'
            - '\ping.exe'
            - '\wordpad.exe'
            - '\write.exe'
        GrantedAccess: '0x1FFFFF' # PROCESS_ALL_ACCESS - All possible access rights for a process object.
    condition: selection
falsepositives:
    - Unknown
# Note: please upgrade to a higher level after an initial test/tuning.
level: low

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetImage|endswith:
        - '\calc.exe'
        - '\calculator.exe'
        - '\mspaint.exe'
        - '\notepad.exe'
        - '\ping.exe'
        - '\wordpad.exe'
        - '\write.exe'
    GrantedAccess: '0x1FFFFF'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
GrantedAccesseq
  • 0x1FFFFF corpus 9 (sigma 7, splunk 1, kusto 1)
field:"GrantedAccess" kind:eq value:"0x1FFFFF"
TargetImageends_with
  • \calc.exe corpus 2 (sigma 2)
  • \calculator.exe corpus 2 (sigma 2)
  • \mspaint.exe corpus 2 (sigma 2)
  • \notepad.exe corpus 2 (sigma 2)
  • \ping.exe corpus 2 (sigma 2)
  • \wordpad.exe corpus 2 (sigma 2)
  • \write.exe corpus 2 (sigma 2)
field:"TargetImage" kind:ends_with