TMA-LNX-NET-SYNCOOKIES
Ensure TCP SYN cookies are enabled
MediumLevel 1Automatedlinux
Description
Kernel parameter net.ipv4.tcp_syncookies should be 1.
How it is checked
Audit method: Shell command
shell
sysctl -n net.ipv4.tcp_syncookies- Expected output
1
How it is fixed
Fix method: Shell command
shell
sysctl -w net.ipv4.tcp_syncookies=1 && printf 'net.ipv4.tcp_syncookies = 1\n' > /etc/sysctl.d/60-tmaegis-net_ipv4_tcp_syncookies.confProperties
- Operating systems
- ubuntu-22.04, ubuntu-24.04, rocky-9
- Tags
- kernelsysctlnetwork
- Reference
- CIS Linux Benchmark - Network Configuration / Kernel Parameters (verify section number for your distro release)
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
shell
tmaegis scan --target linux