A vulnerability in the Indexing Service could allow remote code execution. This vulnerability involves specially formed queries that are longer than 62 characters. Security update 871250 addresses this vulnerability. This article describes a technique that will help prevent an attacker from trying to exploit this vulnerability on computers that do not have security update 871250 applied.

The operating system software development kit (SDK) includes sample code (Query.asp) for querying the Indexing Service. Query.asp uses Microsoft Internet Information Services (IIS) and the Indexing Service's IXSSO query object. The lines in bold in the following example demonstrate additional code that can be added to Query.asp to limit query length. This additional code will help prevent attempts to exploit this vulnerability. You can update other operating system SDK sample query pages in a similar manner.

    if right(SearchString, 1) = chr(34) then
            SrchStrLen = SrchStrLen-1
            SearchString = left(SearchString, SrchStrLen)
    end if

    SrchStrLen = len( SearchString )
    if SrchStrLen > 60 then
            SrchStrLen = 60
            SearchString = left( SearchString, 60 )
    end if

    if Advanced<> "on" then
      CompSearch = "{freetext} " &  SearchString & "{/freetext}"
    else
      CompSearch = SearchString
    end if

    set Q = Server.CreateObject("ixsso.Query")
    set Util = Server.CreateObject("ixsso.Util")

For additional information about security update 871250, click the following article number to view the article in the Microsoft Knowledge Base: