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Dom Mike
Dom Mike

This document discusses various network attack tools and techniques, including sniffers, spoofing, and session hijacking. Sniffers like tcpdump and windump allow attackers to see all network traffic, including usernames and passwords. Session hijacking involves stealing active user sessions through sniffing and spoofing. The document also describes defenses like HTTPS, SSH, and monitoring for spoofing attacks.

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Data Attacks Using Network By Uza!R_Ahmed
Data Attack In computer and computer networks an attack is any attempt to destroy, expose, alter, disable, steal or gain unauthorized access to or make unauthorized use of an asset.
Tools used in Network Attacks Sniffing Spoofing Session hijacking Netcat
Sniffer Allows attacker to see everything sent across the network, including userIDs and passwords Tcpdump http://www.tcpdump.org Windump http://netgroup-serv.polito.it/windump Snort http://www.snort.org Ethereal http://www.ethereal.com Sniffit http://reptile.rug.ac.be/~coder/sniffit/sniffit.html Dsniff http://www.monkey.org/~dugsong/dsniff
Island Hopping Attack Attacker initially takes over a machine via some exploit Attacker installs a sniffer to capture userIDs and passwords to take over other machines
Figure An island hopping attack
Passive Sniffers Sniffers that passively wait for traffic to be sent to them Well suited for hub environment Snort Sniffit
Figure A LAN implemented with a hub
Sniffit in Interactive Mode Useful for monitoring session-oriented applications such as telnet and ftp Activated by starting sniffit with -i option Sorts packets into sessions based on IP addresses and port numbers Identifies userIDs and passwords Allows attacker to watch keystrokes of victim in real time.
Switched Ethernet LANs Forwards network packets based on the destination MAC address in the Ethernet header
Figure A LAN implemented with a switch
Active Sniffers Effective in sniffing switched LANs Injects traffic into the LAN to redirect victims traffic to attacker
Figure In a person-in-the-middle attack, the attacker can grab or alter traffic between Alice and Bob
Sniffing Defenses Use HTTPS for encrypted web traffic Use SSH for encrypted login sessions Avoid using Telnet Use S/MIME or PGP for encrypted email Pay attention to warning messages on your browser and SSH client
Network-based Session Hijacking Attack based on sniffing and spoofing Occurs when attacker steals user session such as telent, rlogin, or FTP. Innocent user thinks that his session was lost, not stolen Attacker sits on a network segment where traffic between victim and server can be seen Attacker injects spoofed packets contain source IP address of victim with proper TCP sequence numbers If hijack is successful, server will obey all commands sent by attacker.
Figure A network-based session hijacking scenario
Session Hijacking Defenses Use SSH or VPN for securing sessions Attackers will not have the keys to encrypt or decrypt traffic Pay attention to warning messages about any change of public key on server since this may be a person-in-the-middle attack
Netcat Network version of cat utility Allows user to move data across a network using any TCP or UDP port Runs on both Unix and Windows NT Netcat executable nc operates in two modes Client mode allows user to initiate connection to any TCP or UDP on a remote machine and to take input data from standard input (eg keyboard or output of pipe) Listen mode (-l option) opens any specified TCP or UDP port on local system and waits for incoming connection and data through port. Data collected is sent to standard output (eg. Screen or input of pipe)
Uzair ppt

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Uzair ppt

  • 1. Data Attacks Using Network By Uza!R_Ahmed
  • 2. Data Attack In computer and computer networks an attack is any attempt to destroy, expose, alter, disable, steal or gain unauthorized access to or make unauthorized use of an asset.
  • 3. Tools used in Network Attacks Sniffing Spoofing Session hijacking Netcat
  • 4. Sniffer Allows attacker to see everything sent across the network, including userIDs and passwords Tcpdump http://www.tcpdump.org Windump http://netgroup-serv.polito.it/windump Snort http://www.snort.org Ethereal http://www.ethereal.com Sniffit http://reptile.rug.ac.be/~coder/sniffit/sniffit.html Dsniff http://www.monkey.org/~dugsong/dsniff
  • 5. Island Hopping Attack Attacker initially takes over a machine via some exploit Attacker installs a sniffer to capture userIDs and passwords to take over other machines
  • 6. Figure An island hopping attack
  • 7. Passive Sniffers Sniffers that passively wait for traffic to be sent to them Well suited for hub environment Snort Sniffit
  • 8. Figure A LAN implemented with a hub
  • 9. Sniffit in Interactive Mode Useful for monitoring session-oriented applications such as telnet and ftp Activated by starting sniffit with -i option Sorts packets into sessions based on IP addresses and port numbers Identifies userIDs and passwords Allows attacker to watch keystrokes of victim in real time.
  • 10. Switched Ethernet LANs Forwards network packets based on the destination MAC address in the Ethernet header
  • 11. Figure A LAN implemented with a switch
  • 12. Active Sniffers Effective in sniffing switched LANs Injects traffic into the LAN to redirect victims traffic to attacker
  • 13. Figure In a person-in-the-middle attack, the attacker can grab or alter traffic between Alice and Bob
  • 14. Sniffing Defenses Use HTTPS for encrypted web traffic Use SSH for encrypted login sessions Avoid using Telnet Use S/MIME or PGP for encrypted email Pay attention to warning messages on your browser and SSH client
  • 15. Network-based Session Hijacking Attack based on sniffing and spoofing Occurs when attacker steals user session such as telent, rlogin, or FTP. Innocent user thinks that his session was lost, not stolen Attacker sits on a network segment where traffic between victim and server can be seen Attacker injects spoofed packets contain source IP address of victim with proper TCP sequence numbers If hijack is successful, server will obey all commands sent by attacker.
  • 16. Figure A network-based session hijacking scenario
  • 17. Session Hijacking Defenses Use SSH or VPN for securing sessions Attackers will not have the keys to encrypt or decrypt traffic Pay attention to warning messages about any change of public key on server since this may be a person-in-the-middle attack
  • 18. Netcat Network version of cat utility Allows user to move data across a network using any TCP or UDP port Runs on both Unix and Windows NT Netcat executable nc operates in two modes Client mode allows user to initiate connection to any TCP or UDP on a remote machine and to take input data from standard input (eg keyboard or output of pipe) Listen mode (-l option) opens any specified TCP or UDP port on local system and waits for incoming connection and data through port. Data collected is sent to standard output (eg. Screen or input of pipe)