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Detection rules › Sigma

Exchange PowerShell Cmdlet History Deleted

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

Detects the deletion of the Exchange PowerShell cmdlet History logs which may indicate an attempt to destroy forensic evidence

MITRE ATT&CK coverage

TacticTechniques
StealthT1070 Indicator Removal

Event coverage

ProviderEventTitle
SysmonEvent ID 23FileDelete (File Delete archived)
SysmonEvent ID 26FileDeleteDetected (File Delete logged)

Rule body yaml

title: Exchange PowerShell Cmdlet History Deleted
id: a55349d8-9588-4c5a-8e3b-1925fe2a4ffe
status: test
description: Detects the deletion of the Exchange PowerShell cmdlet History logs which may indicate an attempt to destroy forensic evidence
references:
    - https://m365internals.com/2022/10/07/hunting-in-on-premises-exchange-server-logs/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-10-26
modified: 2022-12-30
tags:
    - attack.stealth
    - attack.t1070
logsource:
    category: file_delete
    product: windows
detection:
    selection:
        TargetFilename|startswith: '\Logging\CmdletInfra\LocalPowerShell\Cmdlet\'
        TargetFilename|contains: '_Cmdlet_'
    condition: selection
falsepositives:
    - Possible FP during log rotation
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|startswith: '\Logging\CmdletInfra\LocalPowerShell\Cmdlet\'
    TargetFilename|contains: '_Cmdlet_'

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
TargetFilenamematch
  • _Cmdlet_
TargetFilenamestarts_with
  • \Logging\CmdletInfra\LocalPowerShell\Cmdlet\