CVE-2016-4955
The MITRE CVE dictionary describes this issue as:
ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause a denial of service (peer-variable clearing and association outage) by sending (1) a spoofed crypto-NAK packet or (2) a packet with an incorrect MAC value at a certain time.
Find out more about CVE-2016-4955 from the MITRE CVE dictionary dictionary and NIST NVD.
CVSS v2 metrics
NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.
| Base Score | 2.6 |
|---|---|
| Base Metrics | AV:N/AC:H/Au:N/C:N/I:N/A:P |
| Access Vector | Network |
| Access Complexity | High |
| 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).
Affected Packages State
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 7 | ntp | Fix deferred |
| Red Hat Enterprise Linux 6 | ntp | Fix deferred |
| Red Hat Enterprise Linux 5 | ntp | Will not fix |
Acknowledgements
This issue was discovered by Miroslav Lichvar (Red Hat).Mitigation
Disable autokey authentication. Instead, configure ntp to use symmetric key authentication, or no authentication at all (if not required). To configure ntp with symmetric key authentication, follow the steps at https://access.redhat.com/solutions/393663
External References
CVE description copyright © 2017, The MITRE Corporation