The system must use initial TCP sequence numbers most resistant to sequence number guessing attacks.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-12001	GEN003580	SV-12502r2_rule	ECSC-1	Medium

Description
One use of initial TCP sequence numbers is to verify bidirectional communication between two hosts, which provides some protection against spoofed source addresses being used by the connection originator. If the initial TCP sequence numbers for a host can be determined by an attacker, it may be possible to establish a TCP connection from a spoofed source address without bidirectional communication.

Description

One use of initial TCP sequence numbers is to verify bidirectional communication between two hosts, which provides some protection against spoofed source addresses being used by the connection originator. If the initial TCP sequence numbers for a host can be determined by an attacker, it may be possible to establish a TCP connection from a spoofed source address without bidirectional communication.

STIG	Date
UNIX SRG	2013-03-26

Details

Check Text ( C-7965r2_chk )
Determine if the system uses easily guessable initial TCP sequence numbers. If it does, this is a finding.

Fix Text (F-11261r2_fix)
Configure the system to use initial TCP sequence numbers most resistant to sequence number guessing attacks.