Potential CVE-2021-42278 Exploitation Attempt

calendar Jun 20, 2023 · attack.credential_access attack.t1558.003 cve.2021.42278 detection.emerging_threats  ·
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The attacker creates a computer object using those permissions with a password known to her. After that she clears the attribute ServicePrincipalName on the computer object. Because she created the object (CREATOR OWNER), she gets granted additional permissions and can do many changes to the object.

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 1title: Potential CVE-2021-42278 Exploitation Attempt
 2id: 44bbff3e-4ca3-452d-a49a-6efa4cafa06f
 3related:
 4    - id: e80a0fee-1a62-4419-b31e-0d0db6e6013a
 5      type: similar
 6status: test
 7description: |
 8    The attacker creates a computer object using those permissions with a password known to her.
 9    After that she clears the attribute ServicePrincipalName on the computer object.
10    Because she created the object (CREATOR OWNER), she gets granted additional permissions and can do many changes to the object.    
11references:
12    - https://cloudbrothers.info/en/exploit-kerberos-samaccountname-spoofing/
13author: frack113
14date: 2021/12/15
15modified: 2023/04/14
16tags:
17    - attack.credential_access
18    - attack.t1558.003
19    - cve.2021.42278
20    - detection.emerging_threats
21logsource:
22    product: windows
23    service: system
24detection:
25    selection:
26        Provider_Name: 'Microsoft-Windows-Kerberos-Key-Distribution-Center'  # Active Directory
27        EventID:
28            - 35 # PAC without attributes
29            - 36 # Ticket without a PAC
30            - 37 # Ticket without Requestor
31            - 38 # Requestor Mismatch
32    condition: selection
33falsepositives:
34    - Unknown
35fields:
36    - samAccountName
37level: medium

References

  • Exploit samAccountName spoofing with Kerberos

    When Microsoft released the November 2021 patches, the following CVEs caught the eye of many security professionals because they allow impersonation of a domain controller in an Active Directory environment. CVE-2021-42278 - KB5008102 Active Directory Security Accounts Manager hardening changes CVE-2021-42278 addresses a security bypass vulnerability that allows potential attackers to impersonate a domain controller using computer account sAMAccountName spoofing. CVE-2021-42287 KB5008380 Authentication updates CVE-2021-42287 addresses a security bypass vulnerability that affects the Kerberos Privilege Attribute Certificate (PAC) and allows potential attackers to impersonate domain controllers.


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