STIGQter: STIG Summary: Oracle Linux 6 Security Technical Implementation Guide Version: 2 Release: 3 Benchmark Date: 23 Apr 2021:

The system must be configured to use TCP syncookies when experiencing a TCP SYN flood.

DISA Rule

SV-208862r603263_rule

Vulnerability Number

V-208862

Group Title

SRG-OS-000142

Rule Version

OL6-00-000095

Severity

CAT II

CCI(s)

• CCI-001095 - The information system manages excess capacity, bandwidth, or other redundancy to limit the effects of information flooding types of denial of service attacks.

Weight

10

Fix Recommendation

To set the runtime status of the "net.ipv4.tcp_syncookies" kernel parameter, run the following command:

# sysctl -w net.ipv4.tcp_syncookies=1

If this is not the system's default value, add the following line to "/etc/sysctl.conf":

net.ipv4.tcp_syncookies = 1

Check Contents

The status of the "net.ipv4.tcp_syncookies" kernel parameter can be queried by running the following command:

$ sysctl net.ipv4.tcp_syncookies

The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf".

$ grep net.ipv4.tcp_syncookies /etc/sysctl.conf

If the correct value is not returned, this is a finding.

Vulnerability Number

V-208862

Documentable

False

Rule Version

OL6-00-000095

Severity Override Guidance

The status of the "net.ipv4.tcp_syncookies" kernel parameter can be queried by running the following command:

$ sysctl net.ipv4.tcp_syncookies

The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf".

$ grep net.ipv4.tcp_syncookies /etc/sysctl.conf

If the correct value is not returned, this is a finding.

Check Content Reference

M

Target Key

2928

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