NTP Bug 3384

NTP-01-009 NTP: Privileged execution of User Library code (WINDOWS PPSAPI ONLY) (Low)

• Date Resolved: 21 Mar 2017
• References: Sec 3384 / CVE-2017-6455 / VU#325339
• Affects: All Windows versions of ntp-4 that use the PPSAPI, 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 3.8 (AV:L/AC:H/Au:S/C:N/I:N/A:C)
• CVSS3: MED 4.0 CVSS:3.0/AV:L/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H
• Summary: The Windows NT port has the added capability to preload DLLs defined in the inherited global local environment variable PPSAPI_DLLS. The code contained within those libraries is then called from the NTPD service, usually running with elevated privileges. Depending on how securely the machine is setup and configured, if ntpd is configured to use the PPSAPI under Windows this can easily lead to a code injection.
• 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
• Credit: This weakness was discovered by Cure53.