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             AUSCERT External Security Bulletin Redistribution

          JSA11120 - 2021-04 Security Bulletin: Junos OS Evolved:
          Stateless IP firewall filter does not work as expected
                               15 April 2021


        AusCERT Security Bulletin Summary

Product:           Junos OS Evolved: Stateless IP firewall filter
Publisher:         Juniper Networks
Operating System:  Juniper
Impact/Access:     Reduced Security -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-0225  

Original Bulletin: 

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2021-04 Security Bulletin: Junos OS Evolved: Stateless IP firewall filter does not work as expected (CVE-2021-0225)

Article ID  : JSA11120
Last Updated: 14 Apr 2021
Version     : 1.0

Product Affected:
This issue affects Junos OS Evolved 19.1R1-EVO and above prior to
20.3R1-S2-EVO, 20.3R2-EVO.


An Improper Check for Unusual or Exceptional Conditions in Juniper Networks
Junos OS Evolved may cause the stateless firewall filter configuration which
uses the action 'policer' in certain combinations with other options to not
take effect.

An administrator can use the following CLI command to see the failures with
filter configuration:

user@device> show log kfirewall-agent.log | match ERROR
Jul 23 14:16:03 ERROR: filter not supported

This issue affects Juniper Networks Junos OS Evolved:

  o Versions 19.1R1-EVO and above prior to 20.3R1-S2-EVO, 20.3R2-EVO.

This issue does not affect Juniper Networks Junos OS.

The examples of the config stanza affected by this issue:

[firewall policer]
[firewall filter]

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-2021-0225 .


The following software releases have been updated to resolve this specific
issue: Junos OS Evolved: 20.3R1-S2-EVO, 20.3R2-EVO, 20.4R1-EVO, and all
subsequent releases.

This issue is being tracked as 1528091 .


There are no viable workarounds for this issue.

Software releases or updates are available for download at https://
Modification History:

2021-04-14: Initial Publication.

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