Redcannary

rules/windows/registry/registry_event/registry_set_legalnotice_susp_message.yml

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+title: Set Display Ransom Message
+id: 8b9606c9-28be-4a38-b146-0e313cc232c1
+status: experimental
+description: Detect modification of LegalNoticeCaption or LegalNoticeText to set a ransom message
+references:
+    - https://github.com/redcanaryco/atomic-red-team/blob/5c1e6f1b4fafd01c8d1ece85f510160fc1275fbf/atomics/T1491.001/T1491.001.md
+author: frack113
+date: 2022/12/11
+tags:
+    - attack.impact
+    - attack.t1491.001
+logsource:
+    product: windows
+    category: registry_set
+detection:
+    selection:
+        EventType: SetValue
+        TargetObject|contains: 
+            - '\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\LegalNoticeCaption'
+            - '\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\LegalNoticeText'
+        Details|contains:
+            - 'encrypted'
+            - 'Unlock-Password'
+            - 'paying'
+    condition: selection
+falsepositives:
+    - Unknown
+level: high