Lanap CAPTCHA bypass exposure

2006-06-27 / 2006-06-28
Credit: Michael White
Risk: Low
Local: No
Remote: Yes
CWE: CWE-264

CVSS Base Score: 5/10
Impact Subscore: 2.9/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: None
Integrity impact: Partial
Availability impact: None

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Symantec Vulnerability Research Security Advisory Advisory ID : SYMSA-2006-005 Advisory Title: Lanap CAPTCHA bypass exposure Author : Michael White, michael_white (at) symantec (dot) com [email concealed] and Graham Murphy, graham_murphy (at) symantec (dot) com [email concealed] 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 : Overview: The CAPTCHA component for ASP.NET provided by Lanap may be completely bypassed, thus undermining the security benefit of the CAPTCHA technology. Details: 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 entirely. 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. Recommendation: Upgrade to the latest release of the product, BotDetect ASP.NET CAPTCHA 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. CVE-2006-2918 - - - - -------Symantec Vulnerability Research Advisory Information------- For questions about this advisory, or to report an error: research (at) symantec (dot) com [email concealed] For details on Symantec's Vulnerability Reporting Policy: Symantec Vulnerability Research Advisory Archive: Symantec Vulnerability Research GPG Key: - - - - -------------Symantec Product Advisory Information------------- To Report a Security Vulnerability in a Symantec Product: secure (at) symantec (dot) com [email concealed] For general information on Symantec's Product Vulnerability reporting and response: Symantec Product Advisory Archive: Symantec Product Advisory PGP Key: sc - - - - --------------------------------------------------------------- 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 cs_advisories (at) symantec (dot) com. [email concealed] 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. Symantec, Symantec products, and Symantec Consulting Services are registered trademarks of Symantec Corp. and/or affiliated companies in the United States and other countries. All other registered and unregistered trademarks represented in this document are the sole property of their respective companies/owners. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEmZKGuk7IIFI45IARAshOAJ9/x0C9NsmCuo43amlpnOAGKtonPgCg2XPQ dBEH77ubEwyEjWGaFiTt4bw= =QhH/ -----END PGP SIGNATURE-----

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