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                         AUSCERT Security Bulletin

                               ASB-2010.0060
   A vulnerability has been identified in a number of Blue Coat products
                             25 February 2010

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

Product:              SGOS 5
                      SGOS 4
                      PacketShaper
                      ProxyClient
Operating System:     Network Appliance
Impact/Access:        Provide Misleading Information -- Remote/Unauthenticated
Resolution:           None
CVE Names:            CVE-2009-3555  
Member content until: Saturday, March 27 2010
Reference:            ASB-2009.1125.2

OVERVIEW

        A vulnerability has been identifed in the TLS and SSLv3 implementations 
        used by Blue Coat products SGOS 5, SGOS 4, PacketShaper and 
        ProxyClient. 


IMPACT

        This vulnerability has been described by the vendor as:
        
        "TLS and SSLv3 are vulnerable to a man-in-the-middle attack. This 
        vulnerability is due to a design flaw in the cipher suite renegotiation 
        capability of the protocol, not to a particular implementation defect. 
        The vulnerability allows an attacker to insert his own traffic into the
        beginning of the clients application protocol stream." [1]
        
        This vulnerability in the TLS and SSLv3 protocols has been assigned the 
        following CVE reference number: CVE-2009-3555 [2]


MITIGATION

        The vendor has not yet provided a solution to correct this 
        vulnerability, but has issued the following statement:
        
        "Workarounds are being investigated. This advisory will be updated as 
        more information becomes available.
        
        Some TLS/SSL implementations such as OpenSSL have provided a temporary 
        work-around patch which disables renegotiations. This patch will defend 
        against the vulnerability, but may also prevent legitimate 
        renegotiations from taking place thereby causing undesirable 
        connectivity problems. As such, Blue Coat Systems will not be providing 
        this workaround patch to customers. However, an option to disable 
        renegotiation may be offered in conjunction with other measures." [1]


REFERENCES

        [1] Bluecoat Knowledge Base - Security Advisories February 23, 2010 -
            TLS/SSLv3 renegotiation
            https://kb.bluecoat.com/index?page=content&id=SA44

        [2] CVE - CVE-2009-3555 (under review)
            http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3555

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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