3.2.4 Ensure suspicious packets are logged - files net.ipv4.conf.default.log_martians = 1

Information

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.

Solution

Set the following parameters in /etc/sysctl.conf or a /etc/sysctl.d/* 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

See Also

https://workbench.cisecurity.org/files/2619

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-3, 800-53|AU-12, CSCv7|6.2, CSCv7|6.3

Plugin: Unix

Control ID: 61d1c629662af9c6cde462fd31ea3998c0f5846210a3c9084772ef071b3ba7d2