Potential Azure Browser SSO Abuse

 1title: Potential Azure Browser SSO Abuse
 2id: 50f852e6-af22-4c78-9ede-42ef36aa3453
 3status: test
 4description: |
 5    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.
 6    An attacker can use this to authenticate to Azure AD in a browser as that user.    
 7references:
 8    - https://posts.specterops.io/requesting-azure-ad-request-tokens-on-azure-ad-joined-machines-for-browser-sso-2b0409caad30
 9author: Den Iuzvyk
10date: 2020-07-15
11modified: 2023-04-18
12tags:
13    - attack.persistence
14    - attack.defense-evasion
15    - attack.privilege-escalation
16    - attack.t1574.001
17logsource:
18    category: image_load
19    product: windows
20detection:
21    selection:
22        ImageLoaded: 'C:\Windows\System32\MicrosoftAccountTokenProvider.dll'
23    filter_main_bgtaskhost:
24        Image|startswith:
25            - 'C:\Windows\System32\'
26            - 'C:\Windows\SysWOW64\'
27        Image|endswith: '\BackgroundTaskHost.exe'
28        # CommandLine|contains: '-ServerNameBackgroundTaskHost.WebAccountProvider'
29    filter_optional_devenv:
30        Image|startswith:
31            - 'C:\Program Files\Microsoft Visual Studio\'
32            - 'C:\Program Files (x86)\Microsoft Visual Studio\'
33        Image|endswith: '\IDE\devenv.exe'
34    filter_optional_ie:
35        Image:
36            - 'C:\Program Files (x86)\Internet Explorer\iexplore.exe'
37            - 'C:\Program Files\Internet Explorer\iexplore.exe'
38    filter_optional_edge_1:
39        - Image|startswith: 'C:\Program Files (x86)\Microsoft\EdgeWebView\Application\'
40        - Image|endswith: '\WindowsApps\MicrosoftEdge.exe'
41        - Image:
42              - 'C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe'
43              - 'C:\Program Files\Microsoft\Edge\Application\msedge.exe'
44    filter_optional_edge_2:
45        Image|startswith:
46            - 'C:\Program Files (x86)\Microsoft\EdgeCore\'
47            - 'C:\Program Files\Microsoft\EdgeCore\'
48        Image|endswith:
49            - '\msedge.exe'
50            - '\msedgewebview2.exe'
51    filter_optional_onedrive:
52        Image|endswith: '\AppData\Local\Microsoft\OneDrive\OneDrive.exe'
53    filter_optional_null:
54        Image: null
55    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
56falsepositives:
57    - False positives are expected since this rules is only looking for the DLL load event. This rule is better used in correlation with related activity
58level: low