# 3.2.4 Ensure suspicious packets are logged # # Description # =========== # When enabled, this feature logs packets with un-routable source # addresses to the kernel log. # # Rationale # ========= # Enabling this feature and logging these packets allows an administrator # to investigate the possibility that an attacker is sending spoofed # packets to their system. # # Audit # ===== # # Run the following commands and verify output matches: # # # sysctl net.ipv4.conf.all.log_martians # net.ipv4.conf.all.log_martians = 1 # # sysctl net.ipv4.conf.default.log_martians # net.ipv4.conf.default.log_martians = 1 # # Remediation # =========== # # Set the following parameters in the /etc/sysctl.conf file: # # net.ipv4.conf.all.log_martians = 1 # net.ipv4.conf.default.log_martians = 1 # # Run the following commands to set the active kernel parameters: # # # sysctl -w net.ipv4.conf.all.log_martians=1 # # sysctl -w net.ipv4.conf.default.log_martians=1 # # sysctl -w net.ipv4.route.flush=1 parameters: linux: system: kernel: sysctl: net.ipv4.conf.all.log_martians: 1 net.ipv4.conf.default.log_martians: 1