NTP - CVE-2018-7184 Subscribe to Security Advisories

Wednesday, September 12, 2018
Friday, October 11, 2019

A number of vulnerabilities have surfaced in the Operating System (OS) supported in ACOS 3.x and 4.x. Accordingly, the following vulnerabilities are addressed in this document.

Item # Vulnerability ID Score Source Score Summary
1 CVE-2018-7184 CVSS 3.0 7.5 High NTP: Interleaved symmetric mode cannot recover from bad state [1]

Affected Releases

The table below indicates releases of ACOS exposed to these vulnerabilities and ACOS releases that address these issues or are otherwise unaffected by them.

Customers using affected ACOS releases can overcome vulnerability exposures by updating to the indicated resolved release. If the table does not list a corresponding resolved or unaffected release, then no ACOS release update is currently available.

Releases AffectedReleases Resolved or Unaffected

4.1.4 – 4.1.4-P1


4.1.2 – 4.1.2-P4


4.1.1 – 4.1.1-P8


4.1.100 – 4.1.100-P5


4.1.0 – 4.1.0-P11


3.1.0-P1 – 3.2.2-P5

3.2.2-P6, 3.2.3

2.8.2 – 2.8.2-Px

4.1.2-P5, 4.1.4-P2

2.7.2 – 2.7.2-Px

4.1.0-P12, 4.1.4-P9, 4.1.2-P5, 4.1.4-P2

2.7.1-GR1 – 2.7.1-GR1-Px

4.1.0-P12, 4.1.4-P9, 4.1.2-P5, 4.1.4-P2

Workarounds and Mitigations 

Common security best practices in the industry for network appliance management and control planes can enhance protection against remote malicious attacks. Limit the exploitable attack surface for critical, infrastructure, networking equipment through the use of access lists or firewall filters to and from only trusted, administrative networks or hosts.

Software Updates 

Software updates that address these vulnerabilities are or will be published at the following URL:

Vulnerability Details

The following table shares brief descriptions of the vulnerabilities addressed in this document.

Vulnerability IDVulnerability Description

ntpd in ntp 4.2.8p4 before 4.2.8p11 drops bad packets before updating the "received" timestamp, which allows remote attackers to cause a denial of service (disruption) by sending a packet with a zero-origin timestamp causing the association to reset and setting the contents of the packet as the most recent timestamp. This issue is a result of an incomplete fix for CVE-2015-7704.



Modification History 
September 12, 2018

Initial Publication

October 11, 2019

Added 4.1.100 release family.

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