Waraxe IT Security Portal  
  Login or Register
::  Home  ::  Search  ::  Your Account  ::  Forums  ::   Waraxe Advisories  ::  Tools  ::
March 29, 2024
Menu
 Home
 Logout
 Discussions
 Forums
 Members List
 IRC chat
 Tools
 Base64 coder
 MD5 hash
 CRC32 checksum
 ROT13 coder
 SHA-1 hash
 URL-decoder
 Sql Char Encoder
 Affiliates
 y3dips ITsec
 Md5 Cracker
 User Manuals
 AlbumNow
 Content
 Content
 Sections
 FAQ
 Top
 Info
 Feedback
 Recommend Us
 Search
 Journal
 Your Account



User Info
Welcome, Anonymous
Nickname
Password
(Register)

Membership:
Latest: MichaelSnaRe
New Today: 0
New Yesterday: 0
Overall: 9145

People Online:
Visitors: 868
Members: 0
Total: 868
PacketStorm News
·301 Moved Permanently

read more...
Log in Register Forum FAQ Memberlist Search
IT Security and Insecurity Portal

www.waraxe.us Forum Index -> All other security holes -> TCP Session Hijacking >> By 0xbadfaceX
Post new topic  Reply to topic View previous topic :: View next topic 
TCP Session Hijacking >> By 0xbadfaceX
PostPosted: Thu Aug 07, 2008 2:32 pm Reply with quote
0xbadfaceX
Regular user
Regular user
 
Joined: Aug 01, 2008
Posts: 12
Location: .bashrc$>




TCP Session Hijacking.

By 0xbadfaceX. Razz

TCP Session Hijacking allows you to redirect a TCP flow. A hacker can then override protection with a password (like telnet or FTP). The need for listening (sniffing) restricts the scope of this attack to the physical network of the target. Before detailing the attack, we explain some basic principles of TCP.

We will not disclose here the mysteries of the TCP protocol, but only the main points to understand the attack. The header TCP is made up of several fields:

* Port source and destination port, to identify the connection between two machines;
* The sequence number that identifies each byte sent;
* Acknowledgement number that corresponds to the number of acquittal last byte received;
* Flags, along with those that will interest us are:
o SYN which synchronizes the sequence numbers when establishing a connection;
o ACK, the flag of a TCP segment;
o HSP, which tells the receiver to trace the data to the application.



The sequence numbers will change depending on the number of bytes of data sent. The number sequence is represented by Seq, the acknowledgement number is found after the HSP and ACK flags.

The attack creates a state of desynchronization on each side of the TCP connection, making possible the flight session. A connection is out of sync when the sequence number of the next byte sent by the A machine is different number sequence next byte to receive a B. And conversely, there is desynchronization when the sequence number of the next byte sent by the machine B is different from the sequence number of the next byte to be received by A.

When B receives its package, A waits for a package with a number of acquittal x +60. If the next package by B does not have this number of acquittal then A and B are as desynchronized.

Specifically, a pirate with a machine C wants to steal a Telnet session between machines A and B. In a first step, the C machine sniffs the Telnet traffic (TCP port 23) between A and B. Once the attacker thinks A had time to authenticate to the Telnet service on the B machine, it desynchronizes the machine A against B. For this, he forges a package with the source IP address of the A machine and the TCP acknowledgement number expected by B. The B machine accepts the package. In addition desynchronizing the TCP connection, this package allows the attacker to inject a command via Telnet session previously established by A. Indeed, this package can carry data (HSP flag equal to 1).

These techniques are implemented by the hunt program. Wink

_________________
,
View user's profile Send private message Visit poster's website
PostPosted: Mon Aug 11, 2008 1:28 pm Reply with quote
lenny
Valuable expert
Valuable expert
 
Joined: May 15, 2008
Posts: 275




Interesting, thanks for that! Yet another weapon to add to my armoury =]
View user's profile Send private message
TCP Session Hijacking >> By 0xbadfaceX
  www.waraxe.us Forum Index -> All other security holes
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
All times are GMT  
Page 1 of 1  

  
  
 Post new topic  Reply to topic  




Powered by phpBB © 2001-2008 phpBB Group






Space Raider game for Android, free download - Space Raider gameplay video - Zone Raider mobile games
All logos and trademarks in this site are property of their respective owner. The comments and posts are property of their posters, all the rest (c) 2004-2020 Janek Vind "waraxe"
Page Generation: 0.111 Seconds