The Photon operating system must send TCP timestamps.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-258894 | SRG-OS-000480-GPOS-00227 | PHTN-40-000232 | SV-258894r991589_rule | 2024-07-11 | 2 |
| 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. |
| ℹ️ Check |
|---|
| 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 |
|---|
| 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. |