The SLES for vRealize must manage excess capacity, bandwidth, or other redundancy to limit the effects of information flooding types of Denial of Service (DoS) attacks.

From VMware vRealize Operations Manager 6.x SLES Security Technical Implementation Guide

Associated with: CCI-001095

SV-99247r1_rule The SLES for vRealize must manage excess capacity, bandwidth, or other redundancy to limit the effects of information flooding types of Denial of Service (DoS) attacks.

Vulnerability 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

Check that SLES for vRealize has an appropriate TCP backlog queue size to mitigate against TCP SYN flood DOS attacks with the following command: # cat /proc/sys/net/ipv4/tcp_max_syn_backlog The recommended default setting is "1280". If the TCP backlog queue size is not set to "1280", this is a finding.

Fix text

Configure the TCP backlog queue size with the following command: # sed -i 's/^.*\bnet.ipv4.tcp_max_syn_backlog\b.*$/net.ipv4.tcp_max_syn_backlog=1280/' /etc/sysctl.conf Reload sysctl to verify the new change: # sysctl -p

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