ATTENTION: The new home of the Digital Forensics Wiki is at https://forensicswiki.xyz/. Yeah, it's a silly name, but it was cheap.
This wiki will be going offline permanently in the near future. An exact date will be announced soon. Thank you for being a part of this community.
If you wish to work on the new forensicswiki, please join the Google Group forensicswiki-reborn

OS fingerprinting

From ForensicsWiki
Revision as of 02:55, 28 November 2008 by Xnih (Talk | contribs) (Tools)

Jump to: navigation, search

OS fingerprinting is the process of determining the operating system used by a host on a network.

Active fingerprinting

Active fingerprinting is the process of transmitting packets to a remote host and analysing corresponding replies.

Passive fingerprinting

Passive fingerprinting is the process of analysing packets from a host on a network. In this case, fingerprinter acts as a sniffer and doesn't put any traffic on a network.

Fingerprinting techniques

Almost all fingerprinting techniques are based on detecting difference in packets generated by different operating systems.

Common techniques are based on analysing:

  • IP TTL values;
  • IP ID values;
  • TCP Window size;
  • TCP Options (generally, in TCP SYN and SYN+ACK packets);
  • DHCP requests;
  • ICMP requests;
  • HTTP packets (generally, User-Agent field).

Other techniques are based on analysing:

  • Running services;
  • Open port patterns.

Limitations

Many passive fingerprinters are getting confused when analysing packets from a NAT device.

Tools

Active fingerprinters:

Passive fingerprinters:

See Also

Links