NTP Bug 2902

Configuration directives to change "pidfile" and "driftfile" should only be allowed locally.

  • Date Resolved: Stable (4.2.8p4) 21 Oct 2015
  • References: Sec 2902 / CVE-2015-5196
  • Affects: All ntp-4 releases up to, but not including 4.2.8p4, and 4.3.0 up to, but not including 4.3.77
  • CVSS: (AV:N/AC:H/Au:M/C:N/I:C/A:C) Base Score: 6.2 worst case
  • Summary: If ntpd is configured to allow for remote configuration, and if the (possibly spoofed) source IP address is allowed to send remote configuration requests, and if the attacker knows the remote configuration password, it's possible for an attacker to use the "pidfile" or "driftfile" directives to potentially overwrite other files.
  • Mitigation:
    • Implement BCP-38.
    • Upgrade to 4.2.8p4, or later, from the NTP Project Download Page or the NTP Public Services Project Download Page
    • If you cannot upgrade, don't enable remote configuration.
    • If you must enable remote configuration and cannot upgrade, remote configuration of NTF's ntpd requires:
      • an explicitly configured trustedkey, and you should also configure a controlkey.
      • access from a permitted IP. You choose the IPs.
      • authentication. Don't disable it. Practice secure key safety.
    • Monitor your ntpd instances.
  • Credit: This weakness was discovered by Miroslav Lichvar of Red Hat.

This topic: Main > SecurityNotice > NtpBug2902
Topic revision: r1 - 2015-10-23 - 09:05:30 - HarlanStenn
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