Microsoft Exchange Server: Multiple vulnerabilities

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                         ZMCIRT Vulnerability Bulletin

                             ZMC-2021.11.8.0800
                 Microsoft Exchange Server: Multiple vulnerabilities
                               8th November 2021

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Product:          Microsoft Exchange Server
Operating System: Windows
Impact/Access:    Execute Arbitrary Code/Commands -- Existing Account            
                  Provide Misleading Information  -- Remote with User Interaction
Resolution:       Patch/Upgrade
CVE Names:        CVE-2021-42321 CVE-2021-42305 CVE-2021-41349

Comment: Microsoft is aware that exploits for CVE-2021-42321 exist in the wild.

OVERVIEW

        Microsoft has released its monthly security patch update for the
        month of November 2021.
        
        This update resolves 3 vulnerabilities across the following products:
        [1]
        
         Microsoft Exchange Server 2013 Cumulative Update 23
         Microsoft Exchange Server 2016 Cumulative Update 21
         Microsoft Exchange Server 2016 Cumulative Update 22
         Microsoft Exchange Server 2019 Cumulative Update 10
         Microsoft Exchange Server 2019 Cumulative Update 11


IMPACT

        Microsoft has given the following details regarding these vulnerabilities.
        
         Details         Impact                   Severity
         CVE-2021-41349  Spoofing                 Important
         CVE-2021-42305  Spoofing                 Important
         CVE-2021-42321  Remote Code Execution    Important


MITIGATION

        Microsoft recommends updating the software with the version made
        available on the Microsoft Update Catalogue for the following
        Knowledge Base article. [1].
        
         KB5007409


REFERENCES

        [1] Microsoft Security Update Guidance
            https://portal.msrc.microsoft.com/en-us/security-guidance





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