Type securityvulns
Reporter Securityvulns
Modified 2006-06-25T00:00:00



Symantec Vulnerability Research Security Advisory

Advisory ID : SYMSA-2006-005 Advisory Title: Lanap CAPTCHA bypass exposure Author : Michael White, and Graham Murphy, Release Date : 23-06-2006 Application : BotDetect Lanap CAPTCHA component Platform : ASP.NET Severity : Low/Limited exposure Vendor status : Vendor verified, patch available CVE Number : CVE-2006-2918 Reference :


    The CAPTCHA component for ASP.NET provided by Lanap may be
    completely bypassed, thus undermining the security benefit
    of the CAPTCHA technology.


    During a consulting engagement, Symantec identified that the
    Lanap CAPTCHA component stores the UUID and hash for a given
    CAPTCHA within the page ViewState. By replaying the ViewState
    for a known number, a remote attacker may avoid the CAPTCHA

    This behaviour is dependent on the way in which the Lanap
    component is integrated, however numerous examples including
    Lanap's demo code are identified as exhibiting this behaviour.

Vendor Response:

    The above vulnerability has been fixed in the latest release
    of the product, BotDetect ASP.NET CAPTCHA

    Licensed and evaluation versions of Lanap BotDetect ASP.NET
    CAPTCHA are available for customer download from the Lanap
    website at

    If there are any further questions about this statement, please
    contact Lanap support.


    Upgrade to the latest release of the product,

Common Vulnerabilities and Exposures (CVE) Information:

The Common Vulnerabilities and Exposures (CVE) project has assigned the following names to these issues. These are candidates for inclusion in the CVE list (, which standardizes names for security problems.


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Copyright (c) 2006 by Symantec Corp. Permission to redistribute this alert electronically is granted as long as it is not edited in any way unless authorized by Symantec Consulting Services. Reprinting the whole or part of this alert in any medium other than electronically requires permission from

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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