mediumnetworkverified ✓rollback-safe
Ensure tcp syn cookies is enabled
sysctl-tcp-syncookies · UBUNTU ≥ 22, RHEL ≥ 8 · 1 impl
Description
The kernel parameter(s) net.ipv4.tcp_syncookies must be configured to enforce this network security control.
Rationale
Improper network kernel parameters can allow network-based attacks including packet redirection, source routing, and denial of service.
Check → Remediate
Checksysctl_value
- key:
- net.ipv4.tcp_syncookies
- expected:
- 1
Remediatesysctl_set
- key:
- net.ipv4.tcp_syncookies
- value:
- 1
Framework references
CIS
rhel9 3.3.10rhel8 3.3.1.18rhel10 3.3.1.18ubuntu24 3.3.1.18ubuntu22 3.3.1.18
STIG
V-257957V-270753 / UBTU-24-600190V-260522 / UBTU-22-253010V-281340 / RHEL-10-800080
NIST 800-53
SC-7CM-7SC-5
Live verification
rhel10:checkrhel8:checkrhel9:checkubuntu22:checkubuntu24:checkubuntu26:check
#sysctl#networking#hardening