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Detection rules › Sigma

Command Line Execution with Suspicious URL and AppData Strings

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

Detects a suspicious command line execution that includes an URL and AppData string in the command line parameters as used by several droppers (js/vbs > powershell)

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell, T1059.003 Command and Scripting Interpreter: Windows Command Shell
Command & ControlT1105 Ingress Tool Transfer

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

title: Command Line Execution with Suspicious URL and AppData Strings
id: 1ac8666b-046f-4201-8aba-1951aaec03a3
status: test
description: Detects a suspicious command line execution that includes an URL and AppData string in the command line parameters as used by several droppers (js/vbs > powershell)
references:
    - https://www.hybrid-analysis.com/sample/3a1f01206684410dbe8f1900bbeaaa543adfcd07368ba646b499fa5274b9edf6?environmentId=100
    - https://www.hybrid-analysis.com/sample/f16c729aad5c74f19784a24257236a8bbe27f7cdc4a89806031ec7f1bebbd475?environmentId=100
author: Florian Roth (Nextron Systems), Jonhnathan Ribeiro, oscd.community
date: 2019-01-16
modified: 2021-11-27
tags:
    - attack.execution
    - attack.command-and-control
    - attack.t1059.003
    - attack.t1059.001
    - attack.t1105
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\cmd.exe'
        CommandLine|contains|all:
            - 'http' # captures both http and https
            - '://'
            - '%AppData%'
    condition: selection
falsepositives:
    - High
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\cmd.exe'
    CommandLine|contains|all:
        - 'http'
        - '://'
        - '%AppData%'

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
  • %AppData% corpus 13 (sigma 11, chronicle 2)
  • :// corpus 3 (sigma 3)
  • http corpus 39 (sigma 34, elastic 2, chronicle 2, splunk 1)
Imageends_with
  • \cmd.exe corpus 130 (sigma 130)