2015-07 Security Bulletin: Junos: QFX5100/EX4600 Denial of service vulnerability (CVE-2015-5357)

Product Affected:This issue can affect the EX4600, QFX3500, QFX3600, and QFX5100 switches running Junos OS 13.2X51-D15 and higher.

Problem:A high CPU consumption denial of service vulnerability exists in the EX4600 and QFX Series switches listed above. This issue can be triggered by remote unauthenticated network-based attackers. This issue was caused by a regression introduced in Junos OS 13.1X51-D15 and higher. Earlier releases are unaffected by this vulnerability. Juniper SIRT is not aware of any malicious exploitation of this vulnerability. This issue has been assigned CVE-2015-5357.

Solution:The following software releases have been updated to resolve this specific issue: Junos OS 13.2X51-D26, 13.2X51-D30, 14.1X53-D10, and all subsequent releases. This issue is being tracked as PR 959279 and is visible on the Customer Support website. KB16765 – “In which releases are vulnerabilities fixed?” describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.

Workaround:It is good security practice to limit the exploitable attack surface of critical infrastructure networking equipment by designing a control plane firewall filter to block all incoming traffic except for those services and ports explicitly needed. Use access lists or firewall filters to limit access to the router only from trusted, administrative networks or hosts.

Implementation:How to obtain fixed software: Security vulnerabilities in Junos are fixed in the next available Maintenance Release of each supported Junos version. In some cases, a Maintenance Release is not planned to be available in an appropriate time-frame. For these cases, Service Releases are made available in order to be more timely. Security Advisory and Security Notices will indicate which Maintenance and Service Releases contain fixes for the issues described. Upon request to JTAC, customers will be provided download instructions for a Service Release. Although Juniper does not provide formal Release Note documentation for a Service Release, a list of “PRs fixed” can be provided on request. Modification History: 2015-07-08: Initial publication

Related Links: CVSS Score:CVSSv2: 5.0 (AV:N/AC:L/Au:N/C:N/I:N/A:P)

Risk Level:Medium

Risk Assessment:Information for how Juniper Networks uses CVSS can be found at KB 16446 “Common Vulnerability Scoring System (CVSS) and Juniper’s Security Advisories.”

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