Check: UBTU-20-010412
Canonical Ubuntu 20.04 LTS STIG:
UBTU-20-010412
(in versions v1 r12 through v1 r1)
Title
The Ubuntu operating system must be configured to use TCP syncookies. (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. 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
Verify the Ubuntu operating system is configured to use TCP syncookies. Check the value of TCP syncookies with the following command: $ sysctl net.ipv4.tcp_syncookies net.ipv4.tcp_syncookies = 1 If the value is not "1", this is a finding. Check the saved value of TCP syncookies with the following command: $ sudo grep -i net.ipv4.tcp_syncookies /etc/sysctl.conf /etc/sysctl.d/* | grep -v '#' If no output is returned, this is a finding.
Fix Text
Configure the Ubuntu operating system to use TCP syncookies by running the following command: $ sudo sysctl -w net.ipv4.tcp_syncookies=1 If "1" is not the system's default value, add or update the following line in "/etc/sysctl.conf": net.ipv4.tcp_syncookies = 1
Additional Identifiers
Rule ID: SV-238333r654174_rule
Vulnerability ID: V-238333
Group Title: SRG-OS-000142-GPOS-00071
Expert Comments
CCIs
Number | Definition |
---|---|
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. |
Controls
Number | Title |
---|---|
SC-5 (2) |
Excess Capacity / Bandwidth / Redundancy |