Name:Suspicious Computer Account Name Change id:35a61ed8-61c4-11ec-bc1e-acde48001122 version:14 date:None author:Mauricio Velazco, Splunk status:production type:TTP Description:The following analytic detects a suspicious computer account name change in Active Directory. It leverages Event ID 4781, which logs account name changes, to identify instances where a computer account name is changed to one that does not end with a `$`. This behavior is significant as it may indicate an attempt to exploit CVE-2021-42278 and CVE-2021-42287, which can lead to domain controller impersonation and privilege escalation. If confirmed malicious, this activity could allow an attacker to gain elevated privileges and potentially control the domain. Data_source:
how_to_implement:To successfully implement this search, you need to be ingesting Windows event logs from your hosts. In addition, the Splunk Windows TA is needed. known_false_positives:Renaming a computer account name to a name that not end with '$' is highly unsual and may not have any legitimate scenarios. References: -https://exploit.ph/cve-2021-42287-cve-2021-42278-weaponisation.html -https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42278 -https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42287 drilldown_searches: name:'View the detection results for - "$dest$" and "$OldTargetUserName$"' search:'%original_detection_search% | search dest = "$dest$" OldTargetUserName = "$OldTargetUserName$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$" and "$OldTargetUserName$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$OldTargetUserName$") | 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:'7d' latest_offset:'0' analytic_story:['Active Directory Privilege Escalation', 'Compromised Windows Host', 'sAMAccountName Spoofing and Domain Controller Impersonation', 'Scattered Lapsus$ Hunters']
