Name:Azure AD High Number Of Failed Authentications For User id:630b1694-210a-48ee-a450-6f79e7679f2c version:5 date:2024-09-30 author:Mauricio Velazco, Splunk status:production type:TTP Description:The following analytic identifies an Azure AD account experiencing more than 20 failed authentication attempts within a 10-minute window. This detection leverages Azure SignInLogs data, specifically monitoring for error code 50126 and unsuccessful authentication attempts. This behavior is significant as it may indicate a brute force attack targeting the account. If confirmed malicious, an attacker could potentially gain unauthorized access, leading to data breaches or further exploitation within the environment. Security teams should adjust the threshold based on their specific environment to reduce false positives. Data_source:
-Azure Active Directory
search:`azure_monitor_aad` category= SignInLogs properties.status.errorCode=50126 properties.authenticationDetails{}.succeeded=false | rename properties.* as * | bucket span=10m _time | stats count min(_time) as firstTime max(_time) as lastTime values(src_ip) as src_ip by user | where count > 20 | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `azure_ad_high_number_of_failed_authentications_for_user_filter`
how_to_implement:You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase (https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Active Directory events into your Splunk environment through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the SignInLogs log category. known_false_positives:A user with more than 20 failed authentication attempts in the span of 5 minutes may also be triggered by a broken application. References: -https://attack.mitre.org/techniques/T1110/ -https://attack.mitre.org/techniques/T1110/001/ drilldown_searches: name:'View the detection results for - "$user$"' search:'%original_detection_search% | search user = "$user$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Compromised User Account' - 'Azure Active Directory Account Takeover' asset_type:Azure Tenant confidence:70 impact:50 message:User $user$ failed to authenticate more than 20 times in the span of 5 minutes. mitre_attack_id: - 'T1110' - 'T1110.001' observable: name:'user' type:'User' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'properties.status.errorCode' - 'category' - 'properties.authenticationDetails' - 'user' - 'properties.ipAddress' risk_score:35 security_domain:identity
