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A  U  S  C  E  R  T                                           A  L  E  R  T

                       AL-2008.0010 -- AUSCERT ALERT
                                   [Win]
     ZDI-08-002: Citrix Presentation Server IMA Service Heap Overflow
                              22 January 2008

===========================================================================

        AusCERT Alert Summary
        ---------------------

Product:              Metaframe Presentation Server 3.0
                      Presentation Server 4.5 and prior
                      Access Essentials 2.0 and prior
                      Desktop Server 1.0
Publisher:            TippingPoint
Operating System:     Windows
Impact:               Execute Arbitrary Code/Commands
Access:               Remote/Unauthenticated
CVE Names:            CVE-2008-0356

Original Bulletin:    
  http://www.zerodayinitiative.com/advisories/ZDI-08-002.html
  http://support.citrix.com/article/CTX114487

Comment: A patch is available from Citrix for this vulnerability, however
         administrators without the ability to immediately patch affected
         systems should consider increased monitoring of TCP ports 2512 and
         2513 for potential exploitation attempts.
         
         Additionally, access to these ports should be restricted to internal
         clients only which may significantly reduce the risk of exploitation.
         

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ZDI-08-002: Citrix Presentation Server IMA Service Heap Overflow 
Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-08-002.html
January 17, 2008

- -- Affected Vendor:
Citrix

- -- Affected Products:
Metaframe Presentation Server 3.0
Presentation Server 4.0, 4.5
Access Essentials 1.0, 1.5, 2.0
Desktop Server 1.0

- -- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability by Digital Vaccine protection filter ID 5469. 
For further product information on the TippingPoint IPS:

    http://www.tippingpoint.com 

- -- Vulnerability Details:
This vulnerability allows attackers to execute arbitrary code on
vulnerable installations of Citrix Presentation Server. Authentication
is not required to exploit this vulnerability.

The specific flaw resides in the Independent Management Architecture
service, ImaSrv.exe, which listens by default on TCP port 2512 or 2513.
The process trusts a user-suppled value as a parameter to a memory
allocation. By supplying a specific value, an undersized heap buffer
may be allocated. Subsequently, an attacker can then overflow that heap
buffer by sending an overly large packet leading to arbitrary code
execution in the context of the SYSTEM user.


- -- Vendor Response:
Citrix has issued an update to correct this vulnerability. More details
can be found at:

http://support.citrix.com/article/CTX114487

- -- Disclosure Timeline:
2007.07.20 - Vulnerability reported to vendor
2008.01.17 - Coordinated public release of advisory

- -- Credit:
This vulnerability was discovered by Eric DETOISIEN.

- -- About the Zero Day Initiative (ZDI):
Established by TippingPoint, The Zero Day Initiative (ZDI) represents 
a best-of-breed model for rewarding security researchers for responsibly
disclosing discovered vulnerabilities.

Researchers interested in getting paid for their security research
through the ZDI can find more information and sign-up at:

    http://www.zerodayinitiative.com

The ZDI is unique in how the acquired vulnerability information is used.
3Com does not re-sell the vulnerability details or any exploit code.
Instead, upon notifying the affected product vendor, 3Com provides its
customers with zero day protection through its intrusion prevention
technology. Explicit details regarding the specifics of the
vulnerability are not exposed to any parties until an official vendor
patch is publicly available. Furthermore, with the altruistic aim of
helping to secure a broader user base, 3Com provides this vulnerability
information confidentially to security vendors (including competitors)
who have a vulnerability protection or mitigation product.

CONFIDENTIALITY NOTICE: This e-mail message, including any attachments,
is being sent by 3Com for the sole use of the intended recipient(s) and
may contain confidential, proprietary and/or privileged information.
Any unauthorized review, use, disclosure and/or distribution by any 
recipient is prohibited.  If you are not the intended recipient, please
delete and/or destroy all copies of this message regardless of form and
any included attachments and notify 3Com immediately by contacting the
sender via reply e-mail or forwarding to 3Com at postmaster@3com.com. 


- --------------------------END INCLUDED TEXT--------------------

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

===========================================================================
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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