Name:Windows Multiple Users Fail To Authenticate Wth ExplicitCredentials id:e61918fa-9ca4-11eb-836c-acde48001122 version:5 date:2024-09-30 author:Mauricio Velazco, Splunk status:production type:TTP Description:The following analytic identifies a source user failing to authenticate with 30 unique users using explicit credentials on a host. It leverages Windows Event 4648, which is generated when a process attempts an account logon by explicitly specifying account credentials. This detection is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges within an Active Directory environment. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, and potential compromise of sensitive information. Data_source:
-Windows Event Log Security 4648
search:`wineventlog_security` EventCode=4648 Caller_User_Name!=*$ Target_User_Name!=*$ | bucket span=5m _time | stats dc(Target_User_Name) AS unique_accounts values(Target_User_Name) as tried_account by _time, Computer, Caller_User_Name | where unique_accounts > 30 | `windows_multiple_users_fail_to_authenticate_wth_explicitcredentials_filter`
how_to_implement:To successfully implement this search, you need to be ingesting Windows Event Logs from domain controllers as well as member servers and workstations. The Advanced Security Audit policy setting `Audit Logon` within `Logon/Logoff` needs to be enabled. known_false_positives:A source user failing attempting to authenticate multiple users on a host is not a common behavior for regular systems. Some applications, however, may exhibit this behavior in which case sets of users hosts can be added to an allow list. Possible false positive scenarios include systems where several users connect to like Mail servers, identity providers, remote desktop services, Citrix, etc. References: -https://attack.mitre.org/techniques/T1110/003/ -https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4648 -https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/basic-audit-logon-events drilldown_searches: name:'View the detection results for - "$Computer$"' search:'%original_detection_search% | search Computer = "$Computer$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$Computer$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$Computer$") 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: - 'Active Directory Password Spraying' - 'Insider Threat' - 'Volt Typhoon' asset_type:Endpoint confidence:70 impact:70 message:Potential password spraying attack from $Computer$ mitre_attack_id: - 'T1110.003' - 'T1110' observable: name:'Computer' - role: - 'Victim' type:'Endpoint' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'EventCode' - 'Target_User_Name' - 'Caller_User_Name' - 'Computer' risk_score:49 security_domain:endpoint
