COMMON ATTACK PATTERN ENUMERATION AND CLASSIFICATIONLive MITRE record

CAPEC-322

TCP (ISN) Greatest Common Divisor Probe

This OS fingerprinting probe sends a number of TCP SYN packets to an open port of a remote machine. The Initial Sequence Number (ISN) in each of the SYN/ACK response packets is analyzed to determine the smallest number that the target host uses when incrementing sequence numbers. This information can be useful for identifying an operating system because particular operating systems and versions increment sequence numbers using different values. The result of the analysis is then compared against a database of OS behaviors to determine the OS type and/or version.

Abstraction

Detailed

Typical severity

Low

Likelihood of attack

Medium

Understand the attack

What is this attack pattern?

This OS fingerprinting probe sends a number of TCP SYN packets to an open port of a remote machine. The Initial Sequence Number (ISN) in each of the SYN/ACK response packets is analyzed to determine the smallest number that the target host uses when incrementing sequence numbers. This information can be useful for identifying an operating system because particular operating systems and versions increment sequence numbers using different values. The result of the analysis is then compared against a database of OS behaviors to determine the OS type and/or version.

Requirements

What does the attack require?

Prerequisites

  • The ability to monitor and interact with network communications.Access to at least one host, and the privileges to interface with the network interface card.

Skills required

Not stated in the MITRE record.

Resources required

  • A tool capable of sending and receiving packets from a remote system.

Impact

What does a successful attack lead to?

Read Data

Affected scopes: Confidentiality

Bypass Protection MechanismHide Activities

Affected scopes: Confidentiality, Access Control, Authorization