feat(rules): Suspicious Vault client DLL load

 Identifies loading of the Vault client DLL by an unusual process. Adversaries can abuse the functions provided by the Credential Vault Client Library to enumerate or harvest saved credentials.

Author: rabbitstack

rules/credential_access_suspicious_vault_client_dll_load.yml

@@ -0,0 +1,59 @@
+name: Suspicious Vault client DLL load
+id: 64af2e2e-2309-4079-9c0f-985f1dd930f5
+version: 1.0.0
+description: |
+  Identifies loading of the Vault client DLL by an unusual process. Adversaries can abuse the functions provided 
+  by the Credential Vault Client Library to enumerate or harvest saved credentials.
+labels:
+  tactic.id: TA0006
+  tactic.name: Credential Access
+  tactic.ref: https://attack.mitre.org/tactics/TA0006/
+  technique.id: T1555
+  technique.name: Credentials from Password Stores
+  technique.ref: https://attack.mitre.org/techniques/T1555/
+  subtechnique.id: T1555.004
+  subtechnique.name: Windows Credential Manager
+  subtechnique.ref: https://attack.mitre.org/techniques/T1555/004/
+
+references:
+  - https://redcanary.com/blog/incident-response/active-breach-evading-defenses/
+  - https://medium.com/threatpunter/detecting-adversary-tradecraft-with-image-load-event-logging-and-eql-8de93338c16
+
+condition: >
+  sequence
+  maxspan 2m
+    |spawn_process and ps.exe != '' 
+      and 
+      not 
+      (
+        ps.child.exe imatches 
+          (
+            '?:\\Windows\\System32\\MDMAppInstaller.exe',
+            '?:\\Windows\\uus\\*\\MoUsoCoreWorker.exe',
+            '?:\\Windows\\Microsoft.NET\\Framework64\\*\\dfsvc.exe',
+            '?:\\Windows\\Microsoft.NET\\Framework64\\*\\mscorsvw.exe',
+            '?:\\Program Files\\*.exe', 
+            '?:\\Program Files (x86)\\*.exe',
+            '?:\\Windows\\winsxs\\*\\TiWorker.exe'
+          )
+          or
+        (ps.child.exe imatches '?:\\WINDOWS\\System32\\taskhostw.exe' and ps.args intersects ('-k', 'netsvcs', '-p', '-s', 'Schedule'))
+          or
+        (ps.child.exe imatches '?:\\Windows\\System32\\RuntimeBroker.exe')
+          or
+        (ps.exe imatches ('?:\\Program Files\\WindowsApps\\Microsoft.*.exe', '?:\\Windows\\Microsoft.NET\\Framework*\\NGenTask.exe'))
+          or
+        (ps.child.exe imatches '?:\\WINDOWS\\System32\\svchost.exe' and ps.child.args intersects ('-k', 'wusvcs', '-p', '-s', 'WaaSMedicSvc'))
+          or
+        (ps.child.exe imatches '?:\\WINDOWS\\System32\\svchost.exe' and ps.child.args intersects ('-k', 'netsvcs', '-p', '-s', 'TokenBroker'))
+          or
+        (ps.child.exe imatches '?:\\WINDOWS\\system32\\BackgroundTaskHost.exe' and ps.child.args not in ('-ServerName:BackgroundTaskHost.WebAccountProvider'))
+      )
+    | by ps.child.uuid
+    |load_dll and image.name ~= 'vaultcli.dll'| by ps.uuid
+
+output: >
+  Suspicious process %2.ps.exe loaded the Credential Vault Client DLL for potential credentials harvesting
+severity: high
+
+min-engine-version: 2.4.0