Microsoft 365 Exchange Safe Attachment Rule Disabled
editMicrosoft 365 Exchange Safe Attachment Rule Disabled
editIdentifies when a safe attachment rule is disabled in Microsoft 365. Safe attachment rules can extend malware protections to include routing all messages and attachments without a known malware signature to a special hypervisor environment. An adversary or insider threat may disable a safe attachment rule to exfiltrate data or evade defenses.
Rule type: query
Rule indices:
- filebeat-*
- logs-o365*
Severity: low
Risk score: 21
Runs every: 5 minutes
Searches indices from: now-30m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Cloud
- Microsoft 365
- Continuous Monitoring
- SecOps
- Configuration Audit
Version: 2 (version history)
Added (Elastic Stack release): 7.11.0
Last modified (Elastic Stack release): 7.11.2
Rule authors: Elastic
Rule license: Elastic License
Potential false positives
editA safe attachment rule may be disabled by a system or network administrator. Verify that the configuration change was expected. Exceptions can be added to this rule to filter expected behavior.
Investigation guide
editThe Microsoft 365 Fleet integration or Filebeat module must be enabled to use this rule.
Rule query
editevent.dataset:o365.audit and event.provider:Exchange and event.category:web and event.action:"Disable-SafeAttachmentRule" and event.outcome:success
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Impair Defenses
- ID: T1562
- Reference URL: https://attack.mitre.org/techniques/T1562/
Rule version history
edit- Version 2 (7.11.2 release)
-
- Formatting only