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Detection rules › Sigma

APT PRIVATELOG Image Load Pattern

Status
test
Severity
high
Log source
product windows, category image_load
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects an image load pattern as seen when a tool named PRIVATELOG is used and rarely observed under legitimate circumstances

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1055 Process Injection
StealthT1055 Process Injection

Event coverage

ProviderEventTitle
SysmonEvent ID 7Image loaded

Rule body yaml

title: APT PRIVATELOG Image Load Pattern
id: 33a2d1dd-f3b0-40bd-8baf-7974468927cc
status: test
description: Detects an image load pattern as seen when a tool named PRIVATELOG is used and rarely observed under legitimate circumstances
references:
    - https://web.archive.org/web/20210901184449/https://www.fireeye.com/blog/threat-research/2021/09/unknown-actor-using-clfs-log-files-for-stealth.html
author: Florian Roth (Nextron Systems)
date: 2021-09-07
modified: 2022-10-09
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055
    - detection.emerging-threats
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith: '\svchost.exe'
        ImageLoaded|endswith: '\clfsw32.dll'
    condition: selection
falsepositives:
    - Rarely observed
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\svchost.exe'
    ImageLoaded|endswith: '\clfsw32.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.

FieldKindValues
Imageends_with
  • \svchost.exe corpus 23 (sigma 23)
ImageLoadedends_with
  • \clfsw32.dll