Changed selections and condition

see manpage for security tool on macOS
https://gist.github.com/Capybara/6228955

rules/linux/macos_creds_from_keychain.yml

@@ -2,20 +2,28 @@ title: Credentials from Password Stores - Keychain
 id: b120b587-a4c2-4b94-875d-99c9807d6955
 status: experimental
 description: Detects passwords dumps from Keychain
-author: Tim Ismilyaev, oscd.community
+author: Tim Ismilyaev, oscd.community, Florian Roth
 date: 2020/10/19
 references:
     - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1555.001/T1555.001.md
+    - https://gist.github.com/Capybara/6228955
 logsource:
     category: process_creation
     product: macos
 detection:
-    any_keychain_call:
-        ProcessName|endswith: '/security'
-    condition: any_keychain_call
+    selection1:
+        Image: '/usr/bin/security'
+        CommandLine|contains:
+            - 'find-certificate'
+            - ' export '
+    selection2:
+        CommandLine|contains:
+            - ' dump-keychain '
+            - ' login-keychain '
+    condition: 1 of them
 falsepositives:
     - Legitimate administration activities
-level: low
+level: medium
 tags:
     - attack.credential_access
-    - attack.t1555.001
+    - attack.t1555.001