NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to being used in distributed denial-of-service (DDoS) attacks. Please also take this opportunity to defeat denial-of-service attacks by implementing Ingress and Egress filtering through BCP38.

ntp-4.2.8p10 was released on 21 March 2017. It addresses 6 medium- and 5 low-severity security issues, 4 informational security topics, 15 bugfixes, and contains other improvements over 4.2.8p9.

Please see the NTP Security Notice for vulnerability and mitigation details.

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NTP Bug 3008

ctl_getitem() return value not always checked

• Date Resolved: Stable (4.2.8p7) 26 Apr 2016; Dev (4.3.92) 26 Apr 2016
• References: Sec 3008 / CVE-2016-2519 / VU#718152
• Affects: All ntp-4 releases up to, but not including 4.2.8p7, and 4.3.0 up to, but not including 4.3.92
• CVSS2: MED 4.9 (AV:N/AC:H/Au:S/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: ntpq and ntpdc can be used to store and retrieve information in ntpd. It is possible to store a data value that is larger than the size of the buffer that the ctl_getitem() function of ntpd uses to report the return value. If the length of the requested data value returned by ctl_getitem() is too large, the value NULL is returned instead. There are 2 cases where the return value from ctl_getitem() was not directly checked to make sure it's not NULL, but there are subsequent INSIST() checks that make sure the return value is not NULL. There are no data values ordinarily stored in ntpd that would exceed this buffer length. But if one has permission to store values and one stores a value that is "too large", then ntpd will abort if an attempt is made to read that oversized value.
• Mitigation:
  • Implement BCP-38.
  • Upgrade to 4.2.8p7, or later, from the NTP Project Download Page or the NTP Public Services Project Download Page
  • Properly monitor your ntpd instances
• Credit: This weakness was discovered by Yihan Lian of the Cloud Security Team, Qihoo 360.