Detection rules › Sigma

UNC2452 Process Creation Patterns

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

Detects a specific process creation patterns as seen used by UNC2452 and provided by Microsoft as Microsoft Defender ATP queries

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: UNC2452 Process Creation Patterns
id: 9be34ad0-b6a7-4fbd-91cf-fc7ec1047f5f
status: test
description: Detects a specific process creation patterns as seen used by UNC2452 and provided by Microsoft as Microsoft Defender ATP queries
references:
    - https://www.microsoft.com/security/blog/2021/01/20/deep-dive-into-the-solorigate-second-stage-activation-from-sunburst-to-teardrop-and-raindrop/
author: Florian Roth (Nextron Systems)
date: 2021-01-22
modified: 2024-09-12
tags:
    - attack.execution
    - attack.t1059.001
    - detection.emerging-threats
    # - sunburst
    # - unc2452
logsource:
    category: process_creation
    product: windows
detection:
    # To avoid writing complex condition. "selection_generic_1" and "selection_generic_2" are the same except for the extension used.
    selection_generic_1:
        CommandLine|contains:
            - '7z.exe a -v500m -mx9 -r0 -p'
            - '7z.exe a -mx9 -r0 -p'
        CommandLine|contains|all:
            - '.zip'
            - '.txt'
    selection_generic_2:
        CommandLine|contains:
            - '7z.exe a -v500m -mx9 -r0 -p'
            - '7z.exe a -mx9 -r0 -p'
        CommandLine|contains|all:
            - '.zip'
            - '.log'
    selection_generic_3:
        ParentCommandLine|contains|all:
            - 'wscript.exe'
            - '.vbs'
        CommandLine|contains|all:
            - 'rundll32.exe'
            - 'C:\Windows'
            - '.dll,Tk_'
    selection_generic_4:
        ParentImage|endswith: '\rundll32.exe'
        ParentCommandLine|contains|all:
            - 'C:\Windows'
            - '.dll'
        CommandLine|contains: 'cmd.exe /C '
    selection_generic_5:
        ParentImage|endswith: '\rundll32.exe'
        Image|endswith: '\dllhost.exe'
        CommandLine: ''
    condition: 1 of selection_generic_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

1 of selection_generic_*

Stage 1: selection_generic_1

selection_generic_1:
    CommandLine|contains:
        - '7z.exe a -v500m -mx9 -r0 -p'
        - '7z.exe a -mx9 -r0 -p'
    CommandLine|contains|all:
        - '.zip'
        - '.txt'

Stage 2: selection_generic_2

selection_generic_2:
    CommandLine|contains:
        - '7z.exe a -v500m -mx9 -r0 -p'
        - '7z.exe a -mx9 -r0 -p'
    CommandLine|contains|all:
        - '.zip'
        - '.log'

Stage 3: selection_generic_3

selection_generic_3:
    ParentCommandLine|contains|all:
        - 'wscript.exe'
        - '.vbs'
    CommandLine|contains|all:
        - 'rundll32.exe'
        - 'C:\Windows'
        - '.dll,Tk_'

Stage 4: selection_generic_4

selection_generic_4:
    ParentImage|endswith: '\rundll32.exe'
    ParentCommandLine|contains|all:
        - 'C:\Windows'
        - '.dll'
    CommandLine|contains: 'cmd.exe /C '

Stage 5: selection_generic_5

selection_generic_5:
    ParentImage|endswith: '\rundll32.exe'
    Image|endswith: '\dllhost.exe'
    CommandLine: ''

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
CommandLinematch
  • .dll,Tk_
  • .log corpus 4 (sigma 4)
  • .txt corpus 9 (sigma 9)
  • .zip corpus 6 (sigma 5, chronicle 1)
  • 7z.exe a -mx9 -r0 -p
  • 7z.exe a -v500m -mx9 -r0 -p
  • C:\Windows
  • cmd.exe /C corpus 6 (sigma 6)
  • rundll32.exe corpus 8 (sigma 8)
Imageends_with
  • \dllhost.exe corpus 11 (sigma 11)
ParentCommandLinematch
  • .dll
  • .vbs corpus 2 (sigma 2)
  • C:\Windows
  • wscript.exe
ParentImageends_with
  • \rundll32.exe corpus 15 (sigma 15)