A denial of service flaw was found in the way NTP hosts that were peering with each other authenticated themselves before updating their internal state variables. An attacker could send packets to one peer host, which could cascade to other peers, and stop the synchronization process among the reached peers.
Find out more about CVE-2015-1799 from the MITRE CVE dictionary dictionary and NIST NVD.
| Base Score | 4.3 |
|---|---|
| Base Metrics | AV:N/AC:M/Au:N/C:N/I:N/A:P |
| Access Vector | Network |
| Access Complexity | Medium |
| Authentication | None |
| Confidentiality Impact | None |
| Integrity Impact | None |
| Availability Impact | Partial |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
| Platform | Errata | Release Date |
|---|---|---|
| Red Hat Enterprise Linux 7 (ntp) | RHSA-2015:2231 | 2015-11-19 |
| Red Hat Enterprise Linux 6 (ntp) | RHSA-2015:1459 | 2015-07-21 |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 5 | ntp | Will not fix |
To work around this issue, instead of configuring NTP hosts as peers with the 'peer' directive, use the 'server' directive on both hosts so that the connection uses a regular client/server mode of operation.
More information about how to configure NTP can be found at:
Autokey authentication between NTP peers is not sufficient to fully mitigate this issue.
Vulmon