The system must provide protection against IP fragmentation attacks.

From AIX 6.1 SECURITY TECHNICAL IMPLEMENTATION GUIDE

Associated with IA controls: ECSC-1

Associated with: CCI-000032

SV-38702r1_rule The system must provide protection against IP fragmentation attacks.

Vulnerability discussion

The parameter ip_nfrag provides an additional layer of protection against IP fragmentation attacks. The value the ip_nfrag specifies is the maximum number of fragments of an IP packet that can be kept in the IP reassembly queue at any time. The default value of this network option is 200. This is a reasonable value for most environments and offers protection from IP fragmentation attacks.

Check content

Check the value of the ip_nfrag parameter. # /usr/sbin/no -o ip_nfrag If the result returned is less than 200, this is a finding.

Fix text

Set the ip_nfrag parameter to 200. # /usr/sbin/no -p -o ip_nfrag=200

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