diff --git a/rules/o365/exfiltration_o365_exchange_transport_rule_mod.toml b/rules/o365/exfiltration_o365_exchange_transport_rule_mod.toml new file mode 100644 index 000000000..5b76e7bd3 --- /dev/null +++ b/rules/o365/exfiltration_o365_exchange_transport_rule_mod.toml @@ -0,0 +1,54 @@ +[metadata] +creation_date = "2020/11/19" +ecs_version = ["1.6.0"] +maturity = "production" +updated_date = "2020/11/19" + +[rule] +author = ["Elastic"] +description = """ +Identifies when a transport rule has been disabled or deleted in Office 365. Mail flow rules (also known as transport +rules) are used to identify and take action on messages that flow through your organization. An adversary or insider +threat may modify a transport rule to exfiltrate data or evade defenses. +""" +false_positives = [ + """ + A transport rule may be modified by a system or network administrator. Verify that the configuration change was + expected. Exceptions can be added to this rule to filter expected behavior. + """, +] +from = "now-30m" +index = ["filebeat-*"] +language = "kuery" +license = "Elastic License" +name = "O365 Exchange Transport Rule Modification" +note = "The O365 Fleet integration or Filebeat module must be enabled to use this rule." +references = [ + "https://docs.microsoft.com/en-us/powershell/module/exchange/remove-transportrule?view=exchange-ps", + "https://docs.microsoft.com/en-us/powershell/module/exchange/disable-transportrule?view=exchange-ps", + "https://docs.microsoft.com/en-us/exchange/security-and-compliance/mail-flow-rules/mail-flow-rules", +] +risk_score = 47 +rule_id = "272a6484-2663-46db-a532-ef734bf9a796" +severity = "medium" +tags = ["Elastic", "Cloud", "Office 365", "Continuous Monitoring", "SecOps", "Configuration Audit"] +type = "query" + +query = ''' +event.dataset:o365.audit and event.provider:Exchange and event.category:web and event.action:("Remove-TransportRule" or "Disable-TransportRule") and event.outcome:success +''' + + +[[rule.threat]] +framework = "MITRE ATT&CK" +[[rule.threat.technique]] +id = "T1537" +name = "Transfer Data to Cloud Account" +reference = "https://attack.mitre.org/techniques/T1537/" + + +[rule.threat.tactic] +id = "TA0010" +name = "Exfiltration" +reference = "https://attack.mitre.org/tactics/TA0010/" +