Added Sigma Rules

rules/Sigma/sysmon_abusing_azure_browser_sso.yml

@@ -0,0 +1,42 @@
+title: Abusing Azure Browser SSO
+author: Den Iuzvyk
+date: 2020/07/15
+description: Detects abusing Azure Browser SSO by requesting OAuth 2.0 refresh tokens
+    for an Azure-AD-authenticated Windows user (i.e. the machine is joined to Azure
+    AD and a user logs in with their Azure AD account) wanting to perform SSO authentication
+    in the browser. An attacker can use this to authenticate to Azure AD in a browser
+    as that user.
+detection:
+    SELECTION_1:
+        EventID: 7
+    SELECTION_2:
+        ImageLoaded: '*MicrosoftAccountTokenProvider.dll'
+    SELECTION_3:
+        Image: '*BackgroundTaskHost.exe'
+    SELECTION_4:
+        Image: '*devenv.exe'
+    SELECTION_5:
+        Image: '*iexplore.exe'
+    SELECTION_6:
+        Image: '*MicrosoftEdge.exe'
+    condition: (SELECTION_1 and SELECTION_2 and  not ((SELECTION_3 or SELECTION_4
+        or SELECTION_5 or SELECTION_6)))
+falsepositives:
+- unknown
+id: 50f852e6-af22-4c78-9ede-42ef36aa3453
+level: high
+logsource:
+    category: image_load
+    product: windows
+modified: 2020/12/23
+references:
+- https://posts.specterops.io/requesting-azure-ad-request-tokens-on-azure-ad-joined-machines-for-browser-sso-2b0409caad30
+status: experimental
+tags:
+- attack.defense_evasion
+- attack.privilege_escalation
+- attack.t1073
+- attack.t1574.002
+yml_filename: sysmon_abusing_azure_browser_sso.yml
+yml_path: /Users/user/Documents/YamatoSecurity/sigma/rules/windows/image_load
+