Vulnerabilities 2009

PR08-07 XSS vulnerabilities and Webroot disclosure within BBC Betsie

• Advisory publicly released: Friday, 6 November 2009
• Vulnerability found: Monday, 28 January 2008
• Vendor informed: Tuesday, 21 July 2009
• Severity level: Medium/High

• Credits
  Richard Brain of ProCheckUp Ltd (www.procheckup.com)
• Description
  Betsie (www.bbc.co.uk/education/betsie) is vulnerable to Cross-Site Scripting, by injecting malicious characters into the requested path.
  Additionally, Betsie discloses the webroot when the parser.pl program is called without any parameters.
• Proof of concept
  XSS
  
  http://target/textonly/1066/</XSS/*-*/STYLE=xss:e/**/xpression(alert('XSS'))
  http://target/cgi-bin/parser.pl/</XSS/*-*/STYLE=xss:e/**/xpression(alert('XSS'))
  
  webroot disclosure:
  
  http://target/cgi-bin/parser.pl/
  http://www.google.co.uk/search?q=%22Use+of+uninitialized+value+in+substitution%22+betsie&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a
• How to fix
  
• Consequences
  An attacker may be able to cause execution of malicious scripting code in the browser of a user who clicks on a link to a Betsie site. Such code would run within the context of the target domain. This type of attack can result in non-persistent defacement of the target site, or the redirection of confidential information (i.e.: session IDs) to unauthorised third parties.
  
  Attackers can redirect victim users to third-party sites. Such behaviour can help attackers perform phishing attacks by redirecting the victim to a spoof login page.
• Client environment
  Microsoft Internet Explorer 7.0.5730.11
• References
  

  
  http://www.procheckup.com/Vulnerabilities

  
  
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