The Photon operating system must send Transmission Control Protocol (TCP) timestamps.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-256576 | SRG-OS-000480-GPOS-00227 | PHTN-30-000107 | SV-256576r991589_rule | 2024-12-16 | 1 |
| 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: # /sbin/sysctl -a --pattern "net.ipv4.tcp_timestamps$" Expected result: net.ipv4.tcp_timestamps = 1 If the output does not match the expected result, this is a finding. |
| ✔️ Fix |
|---|
| At the command line, run the following commands: # sed -i -e "/^net.ipv4.tcp_timestamps/d" /etc/sysctl.conf # echo net.ipv4.tcp_timestamps=1>>/etc/sysctl.conf # /sbin/sysctl --load |