STIGQter: STIG Summary: Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide Version: 2 Release: 6 Benchmark Date: 01 Jul 2026:

The TOSS operating system must be configured to use TCP syncookies.

DISA Rule

SV-252922r958528_rule

Vulnerability Number

V-252922

Group Title

SRG-OS-000142-GPOS-00071

Rule Version

TOSS-04-010110

Severity

CAT II

CCI(s)

• CCI-001095 - Manage capacity, bandwidth, or other redundancy to limit the effects of information flooding types of denial of service attacks.

Weight

10

Fix Recommendation

Configure The TOSS operating system to use TCP syncookies by running the following command:

$ sudo sysctl -w net.ipv4.tcp_syncookies=1

If "1" is not the system's default value, add or update the following line in "/etc/sysctl.conf":

net.ipv4.tcp_syncookies = 1

Check Contents

Verify The TOSS operating system is configured to use TCP syncookies.

Check the value of TCP syncookies with the following command:

$ sysctl net.ipv4.tcp_syncookies
net.ipv4.tcp_syncookies = 1

If the value is not "1", this is a finding.

Check the saved value of TCP syncookies with the following command:

$ sudo grep -i net.ipv4.tcp_syncookies /etc/sysctl.conf /etc/sysctl.d/* | grep -v '#'

If no output is returned, this is a finding.

Vulnerability Number

V-252922

Documentable

False

Rule Version

TOSS-04-010110

Severity Override Guidance

Verify The TOSS operating system is configured to use TCP syncookies.

Check the value of TCP syncookies with the following command:

$ sysctl net.ipv4.tcp_syncookies
net.ipv4.tcp_syncookies = 1

If the value is not "1", this is a finding.

Check the saved value of TCP syncookies with the following command:

$ sudo grep -i net.ipv4.tcp_syncookies /etc/sysctl.conf /etc/sysctl.d/* | grep -v '#'

If no output is returned, this is a finding.

Check Content Reference

M

Target Key

5469