Detection rules › Sigma

Lace Tempest File Indicators

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

Detects PowerShell script file creation with specific names or suffixes which was seen being used often in PowerShell scripts by FIN7

Known false positives

  • Unlikely

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 11: FileCreate

Rule body

title: Lace Tempest File Indicators
id: e94486ea-2650-4548-bf25-88cbd0bb32d7
status: test
description: Detects PowerShell script file creation with specific names or suffixes which was seen being used often in PowerShell scripts by FIN7
references:
    - https://www.sysaid.com/blog/service-desk/on-premise-software-security-vulnerability-notification
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-11-09
tags:
    - attack.execution
    - detection.emerging-threats
logsource:
    category: file_event
    product: windows
detection:
    selection:
        - TargetFilename|endswith:
              - ':\Program Files\SysAidServer\tomcat\webapps\usersfiles\user.exe'
              - ':\Program Files\SysAidServer\tomcat\webapps\usersfiles.war'
              - ':\Program Files\SysAidServer\tomcat\webapps\leave'
        - TargetFilename|contains: ':\Program Files\SysAidServer\tomcat\webapps\user.'
    condition: selection
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    - TargetFilename|endswith:
          - ':\Program Files\SysAidServer\tomcat\webapps\usersfiles\user.exe'
          - ':\Program Files\SysAidServer\tomcat\webapps\usersfiles.war'
          - ':\Program Files\SysAidServer\tomcat\webapps\leave'
    - TargetFilename|contains: ':\Program Files\SysAidServer\tomcat\webapps\user.'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
TargetFilenameends_with
  • :\Program Files\SysAidServer\tomcat\webapps\leave
  • :\Program Files\SysAidServer\tomcat\webapps\usersfiles.war
  • :\Program Files\SysAidServer\tomcat\webapps\usersfiles\user.exe
field:"TargetFilename" kind:ends_with
TargetFilenamematch
  • :\Program Files\SysAidServer\tomcat\webapps\user.
field:"TargetFilename" kind:match value:":\Program Files\SysAidServer\tomcat\webapps\user."