Microsoft Windows Web Proxy Autodiscovery Protocol (WPAD) information disclosure

win-wpad-information-disclosure (33244) The risk level is classified as MediumMedium Risk

Description:

Microsoft Windows could allow a remote attacker from within the local network to obtain sensitive information, caused by a design error in which the Web Proxy Autodiscovery Protocol (WPAD) is used without static WPAD entries by default. By registering a specially-crafted WPAD entry in DNS or in WINS, an attacker could force the victim to route Internet traffic through a malicious proxy server.

*CVSS:

Base Score: 3.5
  Access Vector: Remote
  Access Complexity: Low
  Authentication: Not Required
  Confidentiality Impact: Partial
  Integrity Impact: None
  Availability Impact: None
 
Temporal Score: 2.7
  Exploitability: Unproven
  Remediation Level: Workaround
  Report Confidence: Uncorroborated

Consequences:

Obtain Information

Remedy:

Refer to Microsoft Knowledge Base Article 934864 for workaround information. See References.

References:

  • Microsoft Knowledge Base Article 934864: How to configure Microsoft DNS and WINS to reserve WPAD registration.
  • CVE-2007-1692: The default configuration of Microsoft Windows uses the Web Proxy Autodiscovery Protocol (WPAD) without static WPAD entries, which might allow remote attackers to intercept web traffic by registering a proxy server using WINS or DNS, then responding to WPAD requests, as demonstrated using Internet Explorer. NOTE: it could be argued that if an attacker already has control over WINS/DNS, then web traffic could already be intercepted by modifying WINS or DNS records, so this would not cross privilege boundaries and would not be a vulnerability. It has also been reported that DHCP is an alternate attack vector.
  • OSVDB ID: 34103: Microsoft Windows Web Proxy Autodiscovery Protocol (WPAD) DNS Subversion
  • OSVDB ID: 52520: Microsoft Windows WPAD WINS Server Registration Web Proxy MiTM Weakness

Platforms Affected:

  • Microsoft Small Business Server 2000
  • Microsoft Windows 2000
  • Microsoft Windows 2003 Server R2 x64 Datacenter

Reported:

Mar 27, 2007

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The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall IBM be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.

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