Detection rules › Sigma

Potential RDP Tunneling Via Plink

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

Execution of plink to perform data exfiltration and tunneling

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1572 Protocol Tunneling

Event coverage

Rule body yaml

title: Potential RDP Tunneling Via Plink
id: f38ce0b9-5e97-4b47-a211-7dc8d8b871da
related:
    - id: f7d7ebd5-a016-46e2-9c54-f9932f2d386d # ssh.exe
      type: similar
status: test
description: Execution of plink to perform data exfiltration and tunneling
references:
    - https://www.microsoft.com/security/blog/2022/07/26/malicious-iis-extensions-quietly-open-persistent-backdoors-into-servers/
author: Florian Roth (Nextron Systems)
date: 2022-08-04
modified: 2023-01-27
tags:
    - attack.command-and-control
    - attack.t1572
logsource:
    category: process_creation
    product: windows
detection:
    selection_a:
        Image|endswith: '\plink.exe'
        CommandLine|contains: ':127.0.0.1:3389'
    selection_b1:
        Image|endswith: '\plink.exe'
        CommandLine|contains: ':3389'
    selection_b2:
        CommandLine|contains:
            - ' -P 443'
            - ' -P 22'
    condition: selection_a or all of selection_b*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection_a or all of selection_b*

Stage 1: selection_a

selection_a:
    Image|endswith: '\plink.exe'
    CommandLine|contains: ':127.0.0.1:3389'

Stage 2: selection_b1

selection_b1:
    Image|endswith: '\plink.exe'
    CommandLine|contains: ':3389'

Stage 3: selection_b2

selection_b2:
    CommandLine|contains:
        - ' -P 443'
        - ' -P 22'

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
  • -P 22
  • -P 443
  • :127.0.0.1:3389
  • :3389 corpus 3 (sigma 3)
Imageends_with
  • \plink.exe corpus 2 (sigma 2)