The Photon operating system must send TCP timestamps.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-258894 | PHTN-40-000232 | SV-258894r991589_rule | Medium |
| Description |
| TCP timestamps are used to provide protection against wrapped sequence numbers. It is possible to calculate system uptime (and boot time) by analyzing TCP timestamps. These calculated uptimes can help a bad actor in determining likely patch levels for vulnerabilities. |
| STIG | Date |
| VMware vSphere 8.0 vCenter Appliance Photon OS 4.0 Security Technical Implementation Guide | 2024-07-11 |
Details
| Check Text (C-62634r933741_chk) |
| At the command line, run the following command to verify TCP timestamps are enabled: # /sbin/sysctl net.ipv4.tcp_timestamps Expected result: net.ipv4.tcp_timestamps = 1 If the "net.ipv4.tcp_timestamps" kernel parameter is not set to "1", this is a finding. |
| Fix Text (F-62543r933742_fix) |
| Navigate to and open: /etc/sysctl.d/zz-stig-hardening.conf Add or update the following line: net.ipv4.tcp_timestamps = 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. |