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Detection rules › Sigma

Suspicious TSCON Start as SYSTEM

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

Detects a tscon.exe start as LOCAL SYSTEM

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1219.002 Remote Access Tools: Remote Desktop Software

Event coverage

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

Rule body yaml

title: Suspicious TSCON Start as SYSTEM
id: 9847f263-4a81-424f-970c-875dab15b79b
status: test
description: Detects a tscon.exe start as LOCAL SYSTEM
references:
    - http://www.korznikov.com/2017/03/0-day-or-feature-privilege-escalation.html
    - https://medium.com/@networksecurity/rdp-hijacking-how-to-hijack-rds-and-remoteapp-sessions-transparently-to-move-through-an-da2a1e73a5f6
    - https://www.ired.team/offensive-security/lateral-movement/t1076-rdp-hijacking-for-lateral-movement
author: Florian Roth (Nextron Systems)
date: 2018-03-17
modified: 2022-05-27
tags:
    - attack.command-and-control
    - attack.t1219.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
        Image|endswith: '\tscon.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    User|contains:
        - 'AUTHORI'
        - 'AUTORI'
    Image|endswith: '\tscon.exe'

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
  • \tscon.exe corpus 2 (sigma 2)
Usermatch
  • AUTHORI corpus 14 (sigma 14)
  • AUTORI corpus 14 (sigma 14)