Microsoft Exchange Server: Multiple vulnerabilities

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                         ZMCIRT Vulnerability Bulletin

                             ZMC-2021.10.13.0800
                   Microsoft Exchange Server: Multiple vulnerabilities
                               13th October 2021

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Product:          Microsoft Exchange Server 2013
                  Microsoft Exchange Server 2016
                  Microsoft Exchange Server 2019
Operating System: Windows
Impact/Access:    Execute Arbitrary Code/Commands -- Existing Account            
                  Increased Privileges            -- Existing Account            
                  Denial of Service               -- Remote/Unauthenticated      
                  Provide Misleading Information  -- Remote with User Interaction
Resolution:       Patch/Upgrade
CVE Names:        CVE-2021-41350 CVE-2021-41348 CVE-2021-34453
                  CVE-2021-26427  

OVERVIEW

        Microsoft has released its monthly security patch update for the
        month of October 2021.
        
        This update resolves 4 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-2021-26427  Remote Code Execution    Important
         CVE-2021-34453  Denial of Service        Important
         CVE-2021-41348  Elevation of Privilege   Important
         CVE-2021-41350  Spoofing                 Important


MITIGATION

        Microsoft recommends updating the software with the version made
        available on the Microsoft Update Catalogue for the following
        Knowledge Base articles. [1].
        
         KB5007011, KB5007012


REFERENCES

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



 
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