The Photon operating system must use Transmission Control Protocol (TCP) syncookies.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-256512 | SRG-OS-000142-GPOS-00071 | PHTN-30-000036 | SV-256512r958528_rule | 2024-12-16 | 1 |
Description
A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected and enables the system to continue servicing valid connection requests.
Satisfies: SRG-OS-000142-GPOS-00071, SRG-OS-000420-GPOS-00186
ℹ️ Check
At the command line, run the following command:
# /sbin/sysctl -a --pattern tcp_syncookies
Expected result:
net.ipv4.tcp_syncookies = 1
If the output does not match the expected result, this is a finding.
✔️ Fix
At the command line, run the following commands:
# sed -i -e "/^net.ipv4.tcp_syncookies/d" /etc/sysctl.conf
# echo net.ipv4.tcp_syncookies=1>>/etc/sysctl.conf
# /sbin/sysctl --load