SV-226887r603265: The system must use initial TCP sequence numbers most resistant to sequence number guessing attacks. | Solaris 10 SPARC STIG SCAP Benchmark

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Assessment Title

Rule Text

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

Description

Discussion Text

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.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000366CCE-4548-4SV-27416V-12001

References

DPMS Target Solaris 10 SPARC DISA DPMS Target Solaris 10 SPARC 4060

Checks

DISA STIG (Manual Reference)

# grep "TCP_STRONG_ISS=2" /etc/default/inetinit
If this variable is not set, this is a finding.

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.fso.solaris11:def:217
# The system must use initial TCP sequence numbers most resistant to sequence number guessing attacks.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Check /etc/default/inetinit variable TCP_STRONG_ISS =2
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  (sed -En 's/^[ \n\t\r]*TCP_STRONG_ISS[ \t]?=[ \t]?([0-9]+)$/\1/p' '/etc/default/inetinit') | grep -qxF '2'
}

if ! test_1; then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# OVAL Definition: oval:mil.disa.fso.solaris11:def:217
if [ -f /etc/default/inetinit ]; then file=$(cat /etc/default/inetinit); if [[ $file == *"TCP_STRONG_ISS=2"* ]]; then echo "PASS"; exit 0; fi; fi; echo "FAIL"; exit 1

Remediation

Edit /etc/default/inetinit and set the TCP_STRONG_ISS parameter to 2.