The Photon operating system must send Transmission Control Protocol (TCP) timestamps.
An XCCDF Rule
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.
- ID
- SV-256576r991589_rule
- Version
- PHTN-30-000107
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
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