NTP Bug 3067

Fix for bug 2085 broke initial sync calculations

  • Date Resolved: 21 Nov 2016
  • References: Sec 3067 / CVE-2016-7433 / VU#633847
  • Affects: ntp-4.2.7p385, up to but not including ntp-4.2.8p9, and ntp-4.3.0 up to, but not including ntp-4.3.94. But the root-distance calculation in general is incorrect in all versions of ntp-4 until this release.
  • CVSS2: LOW 1.2 (AV:L/AC:H/Au:N/C:N/I:N/A:P)
  • CVSS3: LOW 1.6 CVSS:3.0/AV:P/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
  • Summary: Bug 2085 described a condition where the root delay was included twice, causing the jitter value to be higher than expected. Due to a misinterpretation of a small-print variable in The Book, the fix for this problem was incorrect, resulting in a root distance that did not include the peer dispersion. The calculations and formulae have been reviewed and reconciled, and the code has been updated accordingly.
  • Mitigation:
  • Credit: This weakness was discovered independently by Brian Utterback of Oracle, and Sharon Goldberg and Aanchal Malhotra of Boston University.

This topic: Main > SecurityNotice > NtpBug3067
Topic revision: r1 - 2016-11-21 - 14:25:05 - HarlanStenn
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