diff --git a/rules/microsoft-365/credential_access_microsoft_365_brute_force_user_account_attempt.toml b/rules/microsoft-365/credential_access_microsoft_365_brute_force_user_account_attempt.toml index a9d84520e..a982064ad 100644 --- a/rules/microsoft-365/credential_access_microsoft_365_brute_force_user_account_attempt.toml +++ b/rules/microsoft-365/credential_access_microsoft_365_brute_force_user_account_attempt.toml @@ -1,10 +1,10 @@ [metadata] creation_date = "2020/11/30" maturity = "production" -updated_date = "2021/06/09" +updated_date = "2021/06/15" [rule] -author = ["Elastic"] +author = ["Elastic", "Willem D'Haese", "Austin Songer"] description = """ Identifies attempts to brute force a Microsoft 365 user account. An adversary may attempt a brute force attack to obtain unauthorized access to user accounts. @@ -23,6 +23,7 @@ name = "Attempts to Brute Force a Microsoft 365 User Account" note = """## Config The Microsoft 365 Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.""" +references = ["https://blueteamblog.com/7-ways-to-monitor-your-office-365-logs-using-siem"] risk_score = 73 rule_id = "26f68dba-ce29-497b-8e13-b4fde1db5a2d" severity = "high" @@ -30,8 +31,10 @@ tags = ["Elastic", "Cloud", "Microsoft 365", "Continuous Monitoring", "SecOps", type = "threshold" query = ''' -event.dataset:o365.audit and event.provider:(Exchange or AzureActiveDirectory) and event.category:authentication and -event.action:("UserLoginFailed" or "PasswordLogonInitialAuthUsingPassword") and event.outcome:failure +event.dataset:o365.audit and event.provider:(AzureActiveDirectory or Exchange) and + event.category:authentication and event.action:(UserLoginFailed or PasswordLogonInitialAuthUsingPassword) and + not o365.audit.LogonError:(UserAccountNotFound or EntitlementGrantsNotFound or UserStrongAuthEnrollmentRequired or + UserStrongAuthClientAuthNRequired or InvalidReplyTo) and event.outcome:failure '''