NTP Bug 2948

Potential Infinite Loop in ntpq

  • Date Resolved: Stable (4.2.8p6) 19 Jan 2016; Dev (4.3.90) 19 Jan 2016
  • References: Sec 2548 / CVE-2015-8158
  • Affects: All ntp-4 releases up to, but not including 4.2.8p6, and 4.3.0 up to, but not including 4.3.90
  • CVSS2: (AV:N/AC:M/Au:N/C:N/I:N/A:P) Base Score: 4.3 - MEDIUM
  • CVSS3: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N) Base Score: 5.3 - MEDIUM
  • Summary: ntpq processes incoming packets in a loop in getresponse(). The loop's only stopping conditions are receiving a complete and correct response or hitting a small number of error conditions. If the packet contains incorrect values that don't trigger one of the error conditions, the loop continues to receive new packets. Note well, this is an attack against an instance of ntpq, not ntpd, and this attack requires the attacker to do one of the following:
    • Own a malicious NTP server that the client trusts
    • Prevent a legitimate NTP server from sending packets to the ntpq client
    • MITM the ntpq communications between the ntpq client and the NTP server
  • Mitigation:
  • Credit: This weakness was discovered by Jonathan Gardner of Cisco ASIG.

This topic: Main > SecurityNotice > NtpBug2948
Topic revision: r2 - 2016-04-27 - 01:10:04 - SueGraves
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