STIGQter: STIG Summary: VMware vSphere 8.0 vCenter Appliance Photon OS 4.0 Security Technical Implementation Guide Version: 2 Release: 2 Benchmark Date: 01 Jul 2026:

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

DISA Rule

SV-258829r958528_rule

Vulnerability Number

V-258829

Group Title

SRG-OS-000142-GPOS-00071

Rule Version

PHTN-40-000068

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.
• CCI-002385 - Protect against or limit the effects of organization-defined types of denial of service events.

Weight

10

Fix Recommendation

Navigate to and open:

/etc/sysctl.d/zz-stig-hardening.conf

Add or update the following line:

net.ipv4.tcp_syncookies = 1

At the command line, run the following command to load the new configuration:

# /sbin/sysctl --load /etc/sysctl.d/zz-stig-hardening.conf

Note: If the file zz-stig-hardening.conf does not exist, it must be created.

Check Contents

At the command line, run the following command to verify TCP syncookies are enabled:

# /sbin/sysctl net.ipv4.tcp_syncookies

Example result:

net.ipv4.tcp_syncookies = 1

If "net.ipv4.tcp_syncookies" is not set to "1", this is a finding.

Vulnerability Number

V-258829

Documentable

False

Rule Version

PHTN-40-000068

Severity Override Guidance

At the command line, run the following command to verify TCP syncookies are enabled:

# /sbin/sysctl net.ipv4.tcp_syncookies

Example result:

net.ipv4.tcp_syncookies = 1

If "net.ipv4.tcp_syncookies" is not set to "1", this is a finding.

Check Content Reference

M

Target Key

5569