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             AUSCERT External Security Bulletin Redistribution

JSA10942 - 2019-07 Security Bulletin: EX4300 Series: When a firewall filter
        is applied to a loopback interface, other firewall filters
              for multicast traffic may fail (CVE-2019-0048)
                               11 July 2019


        AusCERT Security Bulletin Summary

Product:           Juniper EX4300 Series
Publisher:         Juniper Networks
Operating System:  Juniper
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-0048  

Original Bulletin: 

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2019-07 Security Bulletin: EX4300 Series: When a firewall filter is applied 
to a loopback interface, other firewall filters for multicast traffic may fail 

Article ID:   JSA10942

Last Updated: 10 Jul 2019

Version:      1.0

Product Affected:
This issue affects the EX4300 Series running Junos OS.

On EX4300 Series switches with TCAM optimization enabled, incoming multicast
traffic matches an implicit loopback filter rule first, since it has high
priority. This rule is meant for reserved multicast addresses 224.0.0.x, but
incorrectly matches on 224.x.x.x. Due to this bug, when a firewall filter is
applied on the loopback interface, other firewall filters might stop working
for multicast traffic.

The command ' show firewall filter ' can be used to confirm whether the filter
is working.

This issue only affects the EX4300 switch. No other products or platforms are
affected by this vulnerability.

This issue affects Juniper Networks Junos OS:

  o 14.1X53 versions prior to 14.1X53-D51, 14.1X53-D115 on EX4300 Series;
  o 17.1 versions prior to 17.1R3 on EX4300 Series;
  o 17.2 versions prior to 17.2R3-S2 on EX4300 Series;
  o 17.3 versions prior to 17.3R3-S3 on EX4300 Series;
  o 17.4 versions prior to 17.4R2-S5, 17.4R3 on EX4300 Series;
  o 18.1 versions prior to 18.1R3-S1 on EX4300 Series;
  o 18.2 versions prior to 18.2R2 on EX4300 Series;
  o 18.3 versions prior to 18.3R2 on EX4300 Series.

This issue only affects EX Series switches with TCAM optimization enabled:

set system packet-forwarding-options tcam-group-optimization

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2019-0048 .


The following software releases have been updated to resolve this specific
issue: 14.1X53-D51, 14.1X53-D115, 17.1R3, 17.2R3-S2, 17.3R3-S3, 17.4R2-S5,
17.4R3, 18.1R3-S1, 18.2R2, 18.3R2, 18.4R1, and all subsequent releases.

This issue is being tracked as PR 1392082 which is visible on the Customer
Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of
Engineering (EOE) or End of Life (EOL).

Disabling TCAM optimization will mitigate this issue.
Software Releases, patches and updates are available at https://www.juniper.net
/support/downloads/ .

Modification History:

  o 2019-07-10: Initial Publication

Related Links:

  o KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin
    Publication Process

  o KB16765: In which releases are vulnerabilities fixed

  o KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security

  o Report a Security Vulnerability - How to Contact the Juniper Networks
    Security Incident Response Team

  o CVE-2019-0048 at cve.mitre.org

CVSS Score:
5.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)

Risk Level:

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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