Detection rules › Sigma

Suspicious Scheduled Task Name As GUID

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

Detects creation of a scheduled task with a GUID like name

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: Suspicious Scheduled Task Name As GUID
id: ff2fff64-4cd6-4a2b-ba7d-e28a30bbe66b
status: test
description: Detects creation of a scheduled task with a GUID like name
references:
    - https://thedfirreport.com/2022/10/31/follina-exploit-leads-to-domain-compromise/
    - https://thedfirreport.com/2022/02/21/qbot-and-zerologon-lead-to-full-domain-compromise/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-10-31
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.execution
    - attack.t1053.005
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        Image|endswith: '\schtasks.exe'
        CommandLine|contains: '/Create '
    selection_tn:
        CommandLine|contains:
            # Can start with single or double quote
            - '/TN "{'
            - "/TN '{"
            - "/TN {"
    selection_end:
        CommandLine|contains:
            # Ending of the name to avoid possible FP in the rest of the commandline
            - '}"'
            - "}'"
            - '} '
    condition: all of selection_*
falsepositives:
    - Legitimate software naming their tasks as GUIDs
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    Image|endswith: '\schtasks.exe'
    CommandLine|contains: '/Create '

Stage 2: selection_tn

selection_tn:
    CommandLine|contains:
        - '/TN "{'
        - "/TN '{"
        - "/TN {"

Stage 3: selection_end

selection_end:
    CommandLine|contains:
        - '}"'
        - "}'"
        - '} '

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
  • /Create corpus 5 (sigma 3, splunk 2)
  • /TN "{
  • /TN '{
  • /TN {
  • }
  • }"
  • }'
Imageends_with
  • \schtasks.exe corpus 56 (sigma 56)