NTP before 4.2.8p7 and 4.3.x before 4.3.92 allows remote attackers to cause a denial of service (prevent subsequent authentication) by leveraging knowledge of the controlkey or requestkey and sending a crafted packet to ntpd, which changes the value of trustedkey, controlkey, or requestkey. NOTE: this vulnerability exists because of a CVE-2016-2516 regression.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2016-2517 from the MITRE CVE dictionary dictionary and NIST NVD.
Red Hat Product Security does not consider this to be a security issue. An authenticated user could use various other means to disable access to an NTP server (for example, using the 'restrict' command). To mitigate this issue, disable remote configuration of NTP, or restrict this ability to trusted users.
NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.
| Base Score | 2.1 |
|---|---|
| Base Metrics | AV:N/AC:H/Au:S/C:N/I:N/A:P |
| Access Vector | Network |
| Access Complexity | High |
| Authentication | Single |
| Confidentiality Impact | None |
| Integrity Impact | None |
| Availability Impact | Partial |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 7 | ntp | Will not fix |
| Red Hat Enterprise Linux 6 | ntp | Will not fix |
| Red Hat Enterprise Linux 5 | ntp | Will not fix |
Vulmon