ASP.NET vulnerability!!! 1

[DaZZleD]

Microsoft is currently investigating a reported vulnerability in Microsoft ASP.NET. An attacker can send specially crafted requests to the server and view secured content without providing the proper credentials. This reported vulnerability exists in ASP.NET and does not affect ASP. This issue affects Web content owners who are running any version of ASP.NET on Microsoft Windows 2000, Windows 2000 Server, Windows XP Professional, and
Windows Server 2003.The underlying issue is that ASP.NET is failing to perform proper canonicalization of some URLs. Microsoft Knowledge Base (KB) article 887459, "Programmatically Checking for Canonicalization Issues with ASP.NET," describes how to add additional safeguards to an ASP.NET application to help protect against common canonicalization issues, such as those related to this reported vulnerability.


To reduce riscs, use the following in your Global.asax:

Global.asax code sample (Visual Basic .NET)

Sub Application_BeginRequest(Sender as Object, E as EventArgs)
    If (Request.Path.IndexOf(chr(92)) >= 0 OR _
        System.IO.Path.GetFullPath(Request.PhysicalPath) <> 
Request.PhysicalPath) then
        Throw New HttpException(404, "Not Found")
    End If
End Sub

Global.asax code sample (C#)

void Application_BeginRequest(object source, EventArgs e) {
    if (Request.Path.IndexOf('\\') >= 0 ||
        System.IO.Path.GetFullPath(Request.PhysicalPath) != 
Request.PhysicalPath) {
        throw new HttpException(404, "not found");
    }
}

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"two wrongs don't make a right, but three lefts do" - the unknown sage

 

[DaZZleD]

more resources:

http://www.microsoft.com/security/incident/aspnet.mspx

http://support.microsoft.com/?kbid=887459

--------------------------
"two wrongs don't make a right, but three lefts do" - the unknown sage

 

[DaZZleD]

There is a tool to update all ASP.NET applications on a webserver si more info about it on:

http://www.microsoft.com/security/incident/aspnet.mspx

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"two wrongs don't make a right, but three lefts do" - the unknown sage