Elastic Security Detection Rules

Microsoft 365 Exchange Malware Filter Policy Deletion

Last updated 7 months ago on 2025-01-15
Created 5 years ago on 2020-11-19

About

Identifies when a malware filter policy has been deleted in Microsoft 365. A malware filter policy is used to alert administrators that an internal user sent a message that contained malware. This may indicate an account or machine compromise that would need to be investigated. Deletion of a malware filter policy may be done to evade detection.
Tags
Domain: CloudData Source: Microsoft 365Use Case: Configuration AuditTactic: Defense EvasionLanguage: kuery
Severity
medium
Risk Score
47
MITRE ATT&CK™

Defense Evasion (TA0005)(opens in a new tab or window)

↳ Impair Defenses (T1562)(opens in a new tab or window)

False Positive Examples
A malware filter policy may be deleted by a system or network administrator. Verify that the configuration change was expected. Exceptions can be added to this rule to filter expected behavior.
License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Query (Kibana Query Language)
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
filebeat-*logs-o365*
Related Integrations

o365(opens in a new tab or window)

Query
event.dataset:o365.audit and event.provider:Exchange and event.category:web and event.action:"Remove-MalwareFilterPolicy" and event.outcome:success

Install detection rules in Elastic Security

Detect Microsoft 365 Exchange Malware Filter Policy Deletion in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).