NTP Bug 3389

NTP-01-016 NTP: Denial of Service via Malformed Config (Medium)

• Date Resolved: 21 Mar 2017
• References: Sec 3389 / CVE-2017-6464 / VU#325339
• Affects: All versions of NTP-4, up to but not including ntp-4.2.8p10, and ntp-4.3.0 up to, but not including ntp-4.3.94.
• CVSS2: MED 4.6 (AV:N/AC:H/Au:M/C:N/I:N/A:C)
• CVSS3: MED 4.2 CVSS:3.0/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H
• Summary: A vulnerability found in the NTP server makes it possible for an authenticated remote user to crash ntpd via a malformed mode configuration directive.
• Mitigation:
  • Implement BCP-38.
  • Upgrade to 4.2.8p10, or later, from the NTP Project Download Page or the NTP Public Services Project Download Page
  • Properly monitor your ntpd instances, and auto-restart ntpd (without -g) if it stops running.
• Credit: This weakness was discovered by Cure53.