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                         AUSCERT Security Bulletin

                              ASB-2010.0043.2
             Authentication Bypass vulnerability in XenServer
                             15 February 2010

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:              Citrix XenServer
Operating System:     XEN
Impact/Access:        Unauthorised Access -- Remote/Unauthenticated
Resolution:           Patch/Upgrade
CVE Names:            CVE-2010-0633  
Member content until: Saturday, March  6 2010

Revision History:     February 15 2010: Added CVE
                      February  4 2010: Initial Release

OVERVIEW

        Citrix have reported a vulnerability in XenServer that could result
        in an authentication bypass.


IMPACT

        The vendor has provided the following information regarding this
        vulnerability:
        
        "A vulnerability has been discovered in XenServer that, when 
        triggered, could allow a subset of Xen API (XAPI) calls to be 
        executed without proper authentication." [1]
        
        This vulnerability affects XenServer 5.5 and XenServer 5.0 
        Update 3 and earlier. [1]


MITIGATION

        Citrix have provided a hotfix to address this vulnerability. For 
        download links specific to your system, please see the vendor's
        bulletin. [1]


REFERENCES

        [1] Vulnerability in XenServer Could Result in Authentication Bypass
            http://support.citrix.com/article/CTX123456

AusCERT has made every effort to ensure that the information contained
in this document is accurate.  However, the decision to use the information
described is the responsibility of each user or organisation. The decision to
follow or act on information or advice contained in this security bulletin is
the responsibility of each user or organisation, and should be considered in
accordance with your organisation's site policies and procedures. AusCERT
takes no responsibility for consequences which may arise from following or
acting on information or advice contained in this security bulletin.

If you believe that your computer system has been compromised or attacked in 
any way, we encourage you to let us know by completing the secure National IT 
Incident Reporting Form at:

        http://www.auscert.org.au/render.html?it=3192

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Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours 
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
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