Title

TCP backlog queue sizes must be set appropriately. (Cat II impact)

Discussion

To provide some mitigation to TCP Denial of Service (DoS) attacks, the TCP backlog queue sizes must be set to at least 1280 or in accordance with product-specific guidelines.

Check Content

Check the value of the tcp_syn_rcvd_max parameter. # ndd -get /dev/tcp tcp_syn_rcvd_max If the returned value is less than 1280, this is a finding.

Fix Text

Set the tcp_syn_rcvd_max parameter to 1280. # ndd -set /dev/tcp tcp_syn_rcvd_max 1280 Edit /etc/rc.config.d/nddconf and add/set: TRANSPORT_NAME[x] = tcp NDD_NAME[x] = tcp_syn_rcvd_max NDD_VALUE[x] = 1280

Additional Identifiers

Rule ID: SV-29690r1_rule

Vulnerability ID: V-23741

Group Title: GEN003601

Expert Comments

CCIs tied to check.

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