diff --git a/rules/integrations/o365/defense_evasion_microsoft_365_exchange_malware_filter_policy_deletion.toml b/rules/integrations/o365/defense_evasion_microsoft_365_exchange_malware_filter_policy_deletion.toml index 2406d2fef..c00361977 100644 --- a/rules/integrations/o365/defense_evasion_microsoft_365_exchange_malware_filter_policy_deletion.toml +++ b/rules/integrations/o365/defense_evasion_microsoft_365_exchange_malware_filter_policy_deletion.toml @@ -1,19 +1,19 @@ [metadata] creation_date = "2020/11/19" maturity = "production" -updated_date = "2021/07/20" +updated_date = "2022/01/07" integration = "o365" [rule] author = ["Elastic"] description = """ -Identifies when a malware filter policy has been deleted in Microsoft 365. A malware filter policy is used to alert +Identifies when a malware filter policy has been deleted or disabled 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. """ false_positives = [ """ - A malware filter policy may be deleted by a system or network administrator. Verify that the configuration change + A malware filter policy may be deleted or 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. """, ] @@ -21,12 +21,13 @@ from = "now-30m" index = ["filebeat-*", "logs-o365*"] language = "kuery" license = "Elastic License v2" -name = "Microsoft 365 Exchange Malware Filter Policy Deletion" +name = "Microsoft 365 Exchange Malware Filter Policy Deleted or Disabled" note = """## Config The Microsoft 365 Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.""" references = [ "https://docs.microsoft.com/en-us/powershell/module/exchange/remove-malwarefilterpolicy?view=exchange-ps", + "https://docs.microsoft.com/en-us/powershell/module/exchange/disable-malwarefilterrule?view=exchange-ps" ] risk_score = 47 rule_id = "d743ff2a-203e-4a46-a3e3-40512cfe8fbb" @@ -36,7 +37,7 @@ timestamp_override = "event.ingested" type = "query" query = ''' -event.dataset:o365.audit and event.provider:Exchange and event.category:web and event.action:"Remove-MalwareFilterPolicy" and event.outcome:success +event.dataset:o365.audit and event.provider:Exchange and event.category:web and (event.action:"Remove-MalwareFilterPolicy" or event.action:"Disable-MalwareFilterRule") and event.outcome:success '''