UBTU-24-600190 - Ubuntu 24.04 LTS must be configured to use TCP syncookies.

Information

Denial of service (DoS) occurs when a resource is not available for legitimate users, resulting in the organization not being able to accomplish its mission or causing it to operate at degraded capacity.

Managing excess capacity ensures 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.

Solution

Configure Ubuntu 24.04 LTS to use TCP syncookies with 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

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CAN_Ubuntu_24-04_LTS_V1R1_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5(2), CAT|II, CCI|CCI-001095, Rule-ID|SV-270753r1066748_rule, STIG-ID|UBTU-24-600190, Vuln-ID|V-270753

Plugin: Unix

Control ID: 4e20a17d8ffd5074f72fe8a2b4781f080d59d2e4311cd1a7dd799f624dfca75a