Microsoft ASP.NET Framework bypass security
| ms-aspnet-security-bypass (17644) |  Medium Risk |
Description:
Microsoft ASP.NET Framework could allow a remote attacker to bypass security restrictions, caused by a canonicalization vulnerability. The web.config file prevents access to files unless a user is properly authenticated. A remote attacker could use Mozilla and send a specially-crafted URL request containing a backslash (\) or use Microsoft Internet Explorer to send a request containing a URL encoded backslash (%5C) to bypass this authentication method and gain unauthorized access to the restricted resource.
Consequences:
Bypass Security
Remedy:
Apply the appropriate patch for your system, as listed in the latest Microsoft Security Bulletin. See References.
— OR —
Use Microsoft Automatic Update if it is supported by your operating system. The original bulletin issued by Microsoft has been superseded.
References:
- CIAC Information Bulletin P-127: Microsoft ASP.NET Path Validation Vulnerability.
- Microsoft Corporation Web site: Microsoft ASP.NET ValidatePath Module.
- Microsoft Knowledge Base Article 887459: Programmatically check for canonicalization issues with ASP.NET.
- Microsoft Security Bulletin MS05-004: ASP.NET Path Validation Vulnerability (887219).
- Microsoft Security Bulletin MS07-040: Vulnerabilities in .NET Framework Could Allow Remote Code Execution (931212).
- Microsoft Security Bulletin MS09-061: Vulnerabilities in the Microsoft .NET Common Language Runtime Could Allow Remote Code Execution (974378).
- Microsoft Security Bulletin MS10-041: Vulnerabilities in the Microsoft .NET Framework Could Allow Tampering (981343).
- Microsoft Security Bulletin MS10-060: Vulnerabilities in the Microsoft .NET Common Language Runtime and in Microsoft Silverlight Could Allow Remote Code Execution (2265906).
- Microsoft Security Bulletin MS11-044: Vulnerability in .NET Framework Could Allow Remote Code Execution (2538814).
- Microsoft Security Bulletin MS11-078: Vulnerability in .NET Framework and Microsoft Silverlight Could Allow Remote Code Execution (2604930).
- Microsoft Security Bulletin MS11-078: Vulnerability in .NET Framework and Microsoft Silverlight Could Allow Remote Code Execution (2604930).
- NTBugTraq Mailing List, Thu Oct 07 2004 - 22:12:21 CDT: More details on ASP.NET vulnerability.
- NTBugTraq Mailing List, Tue Sep 14 2004 - 06:42:28 CDT : Security bug in .NET Forms Authentication.
- BID-11342: Microsoft ASP.NET URI Canonicalization Unauthorized Web Access Vulnerability
- CVE-2004-0847: The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restricted directories via a request containing a (1) \ (backslash) or (2) %5C (encoded backslash), aka Path Validation Vulnerability.
- US-CERT VU#283646: Microsoft ASP.NET fails to perform proper canonicalization
Platforms Affected:
- Microsoft .NET Framework 1.0
- Microsoft .NET Framework 1.1
- Microsoft ASP.NET
- Microsoft Windows 2000 SP4
- Microsoft Windows 2000 SP3
- Microsoft Windows 2003 Server
- Microsoft Windows XP Media Center
- Microsoft Windows XP Tablet PC
- Microsoft Windows XP SP1
- Microsoft Windows XP SP2
Reported:
Sep 14, 2004
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