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Detection rules › Sigma

Outlook EnableUnsafeClientMailRules Setting Enabled

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

Detects an attacker trying to enable the outlook security setting "EnableUnsafeClientMailRules" which allows outlook to run applications or execute macros

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter
StealthT1202 Indirect Command Execution

Event coverage

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

Rule body yaml

title: Outlook EnableUnsafeClientMailRules Setting Enabled
id: 55f0a3a1-846e-40eb-8273-677371b8d912
related:
    - id: 6763c6c8-bd01-4687-bc8d-4fa52cf8ba08 # Registry variation
      type: similar
status: test
description: Detects an attacker trying to enable the outlook security setting "EnableUnsafeClientMailRules" which allows outlook to run applications or execute macros
references:
    - https://www.fireeye.com/blog/threat-research/2018/12/overruled-containing-a-potentially-destructive-adversary.html
    - https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=44
    - https://support.microsoft.com/en-us/topic/how-to-control-the-rule-actions-to-start-an-application-or-run-a-macro-in-outlook-2016-and-outlook-2013-e4964b72-173c-959d-5d7b-ead562979048
author: Markus Neis, Nasreddine Bencherchali (Nextron Systems)
date: 2018-12-27
modified: 2023-02-09
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains: '\Outlook\Security\EnableUnsafeClientMailRules'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    CommandLine|contains: '\Outlook\Security\EnableUnsafeClientMailRules'

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
CommandLinematch
  • \Outlook\Security\EnableUnsafeClientMailRules