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-35010r1_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
HP-UX 11.23 Security Technical Implementation Guide	2015-06-12

Details

Check Text ( C-36499r1_chk )
# ndd -get /dev/tcp tcp_isn_passphrase If the value 1 is not returned, this is a finding.

Fix Text (F-31854r1_fix)
# ndd -set /dev/tcp tcp_isn_passphrase Edit /etc/rc.config.d/nddconf and add/set: TRANSPORT_NAME[x] = tcp NDD_NAME[x] = tcp_isn_passphrase NDD_VALUE[x] =