V-238333

Discussion

DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. Managing excess capacity ensures that sufficient capacity is available to counter flooding attacks. Employing increased capacity and service redundancy may reduce the susceptibility to some DoS attacks. Managing excess capacity may include, for example, establishing selected usage priorities, quotas, or partitioning.

Check Content

Verify the Ubuntu operating system is configured to use TCP syncookies. 
 
Check the value of TCP syncookies with the following command: 
 
$ sysctl net.ipv4.tcp_syncookies 
net.ipv4.tcp_syncookies = 1 
 
If the value is not "1", this is a finding. 
 
Check the saved value of TCP syncookies with the following command: 
 
$ sudo grep -i net.ipv4.tcp_syncookies /etc/sysctl.conf /etc/sysctl.d/* | grep -v '#' 
 
If no output is returned, this is a finding.