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Detection rules › Sigma

IIS WebServer Access Logs Deleted

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

Detects the deletion of IIS WebServer access logs which may indicate an attempt to destroy forensic evidence

Known false positives

  • During uninstallation of the IIS service
  • During log rotation

MITRE ATT&CK coverage

TacticTechniques
Stealth

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 23: FileDelete (File Delete archived)
SysmonEvent ID 26: FileDeleteDetected (File Delete logged)

Rule body

title: IIS WebServer Access Logs Deleted
id: 3eb8c339-a765-48cc-a150-4364c04652bf
related:
    - id: 0649be4a-aeb0-45b0-b89e-7f1668f6d9c0
      type: similar
status: test
description: Detects the deletion of IIS WebServer access logs which may indicate an attempt to destroy forensic evidence
references:
    - https://www.elastic.co/guide/en/security/current/webserver-access-logs-deleted.html
author: Tim Rauch (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-16
modified: 2023-02-15
tags:
    - attack.stealth
    - attack.t1070
logsource:
    category: file_delete
    product: windows
detection:
    selection:
        TargetFilename|contains: '\inetpub\logs\LogFiles\'
        TargetFilename|endswith: '.log'
    condition: selection
falsepositives:
    - During uninstallation of the IIS service
    - During log rotation
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|contains: '\inetpub\logs\LogFiles\'
    TargetFilename|endswith: '.log'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
TargetFilenameends_with
  • .log corpus 2 (sigma 2)
field:"TargetFilename" kind:ends_with value:".log"
TargetFilenamematch
  • \inetpub\logs\LogFiles\
field:"TargetFilename" kind:match value:"\inetpub\logs\LogFiles\"