STIGQter STIGQter: STIG Summary: Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide Version: 1 Release: 1 Benchmark Date: 10 Mar 2021:

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

DISA Rule

SV-238333r654174_rule

Vulnerability Number

V-238333

Group Title

SRG-OS-000142-GPOS-00071

Rule Version

UBTU-20-010412

Severity

CAT II

CCI(s)

Weight

10

Fix Recommendation

Configure the Ubuntu 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 Ubuntu 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-238333

Documentable

False

Rule Version

UBTU-20-010412

Severity Override Guidance

Verify the Ubuntu 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

5318

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