Check: PHTN-67-000037
VMware vSphere 6.7 Photon OS STIG:
PHTN-67-000037
(in versions v1 r6 through v1 r2)
Title
The Photon operating system must use TCP syncookies. (Cat II impact)
Discussion
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
Check Content
At the command line, execute 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 Text
Open /etc/sysctl.conf with a text editor. Add or update the following line: net.ipv4.tcp_syncookies=1 Run the following command to load the new setting: # /sbin/sysctl --load
Additional Identifiers
Rule ID: SV-239109r856040_rule
Vulnerability ID: V-239109
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. |
CCI-002385 |
The information system protects against or limits the effects of organization-defined types of denial of service attacks by employing organization-defined security safeguards. |