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.defense-evasion
14    - attack.privilege-escalation
15    - attack.t1574.002
16logsource:
17    category: image_load
18    product: windows
19detection:
20    selection:
21        ImageLoaded: 'C:\Windows\System32\MicrosoftAccountTokenProvider.dll'
22    filter_main_bgtaskhost:
23        Image|startswith:
24            - 'C:\Windows\System32\'
25            - 'C:\Windows\SysWOW64\'
26        Image|endswith: '\BackgroundTaskHost.exe'
27        # CommandLine|contains: '-ServerNameBackgroundTaskHost.WebAccountProvider'
28    filter_optional_devenv:
29        Image|startswith:
30            - 'C:\Program Files\Microsoft Visual Studio\'
31            - 'C:\Program Files (x86)\Microsoft Visual Studio\'
32        Image|endswith: '\IDE\devenv.exe'
33    filter_optional_ie:
34        Image:
35            - 'C:\Program Files (x86)\Internet Explorer\iexplore.exe'
36            - 'C:\Program Files\Internet Explorer\iexplore.exe'
37    filter_optional_edge_1:
38        - Image|startswith: 'C:\Program Files (x86)\Microsoft\EdgeWebView\Application\'
39        - Image|endswith: '\WindowsApps\MicrosoftEdge.exe'
40        - Image:
41              - 'C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe'
42              - 'C:\Program Files\Microsoft\Edge\Application\msedge.exe'
43    filter_optional_edge_2:
44        Image|startswith:
45            - 'C:\Program Files (x86)\Microsoft\EdgeCore\'
46            - 'C:\Program Files\Microsoft\EdgeCore\'
47        Image|endswith:
48            - '\msedge.exe'
49            - '\msedgewebview2.exe'
50    filter_optional_onedrive:
51        Image|endswith: '\AppData\Local\Microsoft\OneDrive\OneDrive.exe'
52    filter_optional_null:
53        Image: null
54    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
55falsepositives:
56    - 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
57level: low