[Full-disclosure] iDEFENSE Security Advisory 04.26.05: Citrix Program Neighborhood Agent Arbitrary Shortcut Creation Vulnerability

From: iDEFENSE Labs (labs-no-reply_at_idefense.com)
Date: 04/26/05

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    Date: Tue, 26 Apr 2005 11:12:04 -0400
    To: <bugtraq@securityfocus.com>, <vulnwatch@vulnwatch.org>, <full-disclosure@lists.grok.org.uk>
    
    

    Citrix Program Neighborhood Agent Arbitrary Shortcut Creation
    Vulnerability

    iDEFENSE Security Advisory 04.26.05
    www.idefense.com/application/poi/display?id=237&type=vulnerabilities
    April 26, 2005

    I. BACKGROUND

    Citrix Program Neighborhood Agent is a part of the Citrix Presentation
    Server Client and facilitates access to Citrix published applications.

    II. DESCRIPTION

    Remote exploitation of a design error in Citrix Systems Inc.'s Program
    Neighborhood Agent allows attackers to create arbitrary shortcuts under
    the privileges of the client user.

    Citrix Program Neighborhood Agent is a part of the Citrix Presentation
    Server Client and facilitates access to Citrix published applications.
    The problem specifically exists in that an attacker who has established
    a malicious server can create arbitrary shortcuts to the client user's
    Startup folder by specifying the following directive:

       <AppInStartmenu value="true" root="programs">startup</AppInStartmenu>

    An attacker can specify the UNC path to an arbitrary malicious binary,
    and this binary will be executed the next time the client user reboots
    with an active network connection.

    III. ANALYSIS

    Successful exploitation allows remote attackers to execute arbitrary
    code under the privileges of the client user. Exploitation requires that
    an attacker establish a malicious server and cause or convince the
    target user to connect to it via the Program Neighborhood Agent. This
    can be accomplished by social engineering or automatically when combined
    with a DNS- or ARP-spoofing attack.

    IV. DETECTION

    iDEFENSE has confirmed the existence of this vulnerability in Citrix
    MetaFrame Program Neighborhood v8.00.24737. It is suspected that earlier
    versions are also vulnerable.

    V. WORKAROUND

    Utilize the server IP address instead of the name to circumvent DNS
    spoofing attacks.

    VI. VENDOR RESPONSE

    A vendor advisory for this vulnerability is available at:
       http://support.citrix.com/kb/entry.jspa?externalID=CTX105650

    Updated clients to address this vulnerability are available at:
       http://www.citrix.com/English/SS/downloads/downloads.asp?dID=2755

    VII. CVE INFORMATION

    The Common Vulnerabilities and Exposures (CVE) project has assigned the
    names CAN-2004-1077 to these issues. This is a candidate for inclusion
    in the CVE list (http://cve.mitre.org), which standardizes names for
    security problems.

    VIII. DISCLOSURE TIMELINE

    11/23/2004 Initial vendor notification
    11/24/2004 Initial vendor response
    04/26/2005 Coordinated public disclosure

    IX. CREDIT

    Patrik Karlsson (cqure.net) is credited with this discovery.

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    X. LEGAL NOTICES

    Copyright (c) 2005 iDEFENSE, Inc.

    Permission is granted for the redistribution of this alert
    electronically. It may not be edited in any way without the express
    written consent of iDEFENSE. If you wish to reprint the whole or any
    part of this alert in any other medium other than electronically, please
    email customerservice@idefense.com for permission.

    Disclaimer: The information in the advisory is believed to be accurate
    at the time of publishing based on currently available information. Use
    of the information constitutes acceptance for use in an AS IS condition.
    There are no warranties with regard to this information. Neither the
    author nor the publisher accepts any liability for any direct, indirect,
    or consequential loss or damage arising from use of, or reliance on,
    this information.
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