Detection rules › Sigma

Tamper With Sophos AV Registry Keys

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

Detects tamper attempts to sophos av functionality via registry key modification

Known false positives

  • Some FP may occur when the feature is disabled by the AV itself, you should always investigate if the action was legitimate

MITRE ATT&CK coverage

TacticTechniques
Defense Impairment

Telemetry coverage

Rule body

title: Tamper With Sophos AV Registry Keys
id: 9f4662ac-17ca-43aa-8f12-5d7b989d0101
status: test
description: Detects tamper attempts to sophos av functionality via registry key modification
references:
    - https://redacted.com/blog/bianlian-ransomware-gang-gives-it-a-go/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-02
modified: 2023-08-17
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains:
            - '\Sophos Endpoint Defense\TamperProtection\Config\SAVEnabled'
            - '\Sophos Endpoint Defense\TamperProtection\Config\SEDEnabled'
            - '\Sophos\SAVService\TamperProtection\Enabled'
        Details: DWORD (0x00000000)
    condition: selection
falsepositives:
    - Some FP may occur when the feature is disabled by the AV itself, you should always investigate if the action was legitimate
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetObject|contains:
        - '\Sophos Endpoint Defense\TamperProtection\Config\SAVEnabled'
        - '\Sophos Endpoint Defense\TamperProtection\Config\SEDEnabled'
        - '\Sophos\SAVService\TamperProtection\Enabled'
    Details: DWORD (0x00000000)

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Detailseq
  • DWORD (0x00000000) corpus 38 (sigma 36, chronicle 2)
field:"Details" kind:eq value:"DWORD (0x00000000)"
TargetObjectmatch
  • \Sophos Endpoint Defense\TamperProtection\Config\SAVEnabled
  • \Sophos Endpoint Defense\TamperProtection\Config\SEDEnabled
  • \Sophos\SAVService\TamperProtection\Enabled
field:"TargetObject" kind:match