Name:Powershell Remove Windows Defender Directory id:adf47620-79fa-11ec-b248-acde48001122 version:5 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects a suspicious PowerShell command attempting to delete the Windows Defender directory. It leverages PowerShell Script Block Logging to identify commands containing "rmdir" and targeting the Windows Defender path. This activity is significant as it may indicate an attempt to disable or corrupt Windows Defender, a key security component. If confirmed malicious, this action could allow an attacker to bypass endpoint protection, facilitating further malicious activities without detection. Data_source:
-Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 ScriptBlockText = "*rmdir *" AND ScriptBlockText = "*\\Microsoft\\Windows Defender*" | stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `powershell_remove_windows_defender_directory_filter`
how_to_implement:To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell. known_false_positives:unknown References: -https://www.microsoft.com/security/blog/2022/01/15/destructive-malware-targeting-ukrainian-organizations/ drilldown_searches: name:'View the detection results for - "$Computer$" and "$UserID$"' search:'%original_detection_search% | search Computer = "$Computer$" UserID = "$UserID$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$Computer$" and "$UserID$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$Computer$", "$UserID$") 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: - 'Data Destruction' - 'WhisperGate' asset_type:Endpoint confidence:90 impact:100 message:suspicious powershell script $ScriptBlockText$ was executed on the $Computer$ mitre_attack_id: - 'T1562.001' - 'T1562' observable: name:'Computer' type:'Hostname' - role: - 'Victim' name:'UserID' type:'User' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'ScriptBlockText' - 'Opcode' - 'Computer' - 'UserID' - 'EventCode' risk_score:90 security_domain:endpoint
