Title

The operating system must protect against or limit the effects of Denial of Service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces. (Cat II impact)

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. This requirement addresses the configuration of the operating system to mitigate the impact of DoS attacks that have occurred or are ongoing on system availability. For each system, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exist to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or establishing memory partitions). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks. Satisfies: SRG-OS-000420-GPOS-00186

Check Content

Verify the operating system protects against or limits the effects of Denial of Service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces. If it does not, this is a finding. Ensure PF is enabled: $ grep pf_ /etc/rc.conf pf_enable="YES" pf_flags="" "pf_enable" must be set to YES. (There may be additional lines.) $ pfctl -s rules pass in inet proto tcp from any to 10.1.1.1 port = http flags S/SA keep state (source-track rule, max-src-conn-rate 100/10, overload <bad_hosts> flush global, src.track 10) If a rule does not exist that contains max-src-conn-rate, to rate limit connections to applicable interfaces, this is a finding.

Fix Text

Configure the operating system to protect against or limit the effects of Denial of Service (DoS) attacks by ensuring the operating system is implementing rate-limiting measures on impacted network interfaces.

Additional Identifiers

Rule ID:

Vulnerability ID: V-1860

Group Title:

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.