ASI Sybase Security Alert: Buffer overflow in DBCC CHECKVERIFY

From: Aaron C. Newman (Application Security, Inc.) (anewman@appsecinc.com)
Date: 11/27/02

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    From: "Aaron C. Newman (Application Security, Inc.)" <anewman@appsecinc.com>
    To: <bugtraq@securityfocus.com>, <vulnwatch@vulnwatch.org>, <NTBUGTRAQ@LISTSERV.NTBUGTRAQ.COM>, <cert@cert.org>
    Date: Wed, 27 Nov 2002 14:14:25 -0500
    
    

    Sybase Adaptive Server buffer overflow in DBCC CHECKVERIFY

    http://www.appsecinc.com/resources/alerts/sybase/02-0001.html

    To determine if you should apply this hot fix, download AppDetective for
    Sybase from http://www.sybasesecurity.net/products/appdetective/sybase/.

    Risk level: High

    Threat: Allows a non-privileged login to gain full control of the server

    Versions Affected: Sybase Adaptive Server 12.0 and 12.5

    Summary:
    Sybase Adaptive Server provides a built-in function called DBCC
    CHECKVERIFY. This function is used to verify the results of the most
    recent run of DBCC CHECKSTORAGE.

    Details:
    DBCC CHECKVERIFY accepts a single parameter that is the name of the
    database to check. DBCC CHECKVERIFY does not validate the length of the
    string passed into the first parameter. This buffer overflow may allow
    an attacker to run arbitrary code under the security context of the
    server.

    Below is an example of overflowing the buffer using the SQL tool
    isql.exe.

    1> declare @test varchar(16384)
    2> select @test = replicate(‘A’, 16384)
    3> DBCC CHECKVERIFY(@test)
    4> go

    Fix:
    You should apply the following patches:
    12.5.0.2 - 11/14/2002
    12.0.0.6 ESD#1 - 11/5/2002

    These patches can be downloaded from http://downloads.sybase.com/swd/swx

    Thank you,
    support@appsecinc.com
    Application Security, Inc.
    phone: 212-490-6022
    fax: 212-490-6456
    -Protection Where It Counts-

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    www.appsecinc.com

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