This article has information on configuring Network Time Protocol (NTP) on NetScaler to prevent traffic amplification attack.

Requirements

Good understanding of NetScaler and NTP.

Background

NTP amplification attack might appear in security scans.

Instructions

To configure NTP on NetScaler to prevent traffic amplification attacks, complete the following step:

1. Replace the following line (if it exists) in "ntp.conf" file with those mentioned in Step 2:
   >  restrict default ignore

2. Add the following lines in file "/etc/ntp.conf":
   # By default, exchange time with everybody, but don't allow configuration:
   restrict -4 default kod notrap nomodify nopeer noquery
   restrict -6 default kod notrap nomodify nopeer noquery

   # Local users may interrogate the ntp server more closely:
   restrict -4 127.0.0.1
   restrict -6 ::1

3. Restart NTP using the following command:
   root@ns#  sh /mpsconfig/ntpd_start
    

Additional Resources

CVE-2013-5211- Vulnerability Summary for CVE-2013-5211