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AUSCERT External Security Bulletin Redistribution
ESB-2020.3717.2
A DNS over TCP packet is not rate-limited accurately using
the single-endpoint DoS device flood vector
9 November 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: BIG-IP
BIG-IP AFM
Publisher: F5 Networks
Operating System: Network Appliance
Impact/Access: Reduced Security -- Unknown/Unspecified
Resolution: Patch/Upgrade
Original Bulletin:
https://support.f5.com/csp/article/K23278332
Revision History: November 9 2020: Point release table updated by vendor
October 29 2020: Initial Release
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K23278332: A DNS over TCP packet is not rate-limited accurately using the
single-endpoint DoS device flood vector
Original Publication Date: 29 Oct, 2020
Latest Publication Date: 07 Nov, 2020
Security Advisory Description
This issue occurs when all of the following conditions are met:
o Setting the correct DNS packet type in the denial-of-service (DoS) device
sweep or flood vector.
o Matching traffic sends DNS over TCP.
Impact
The mitigation for DNS over TCP packets is not working as expected when a
distributed denial-of-service (DDoS) attack occurs.
Symptoms
As a result of this issue, you may encounter the following symptom:
o The DNS over TCP packet is not rate-limited accurately by the DoS device
sweep and flood vector.
Security Advisory Status
F5 Product Development has assigned ID 852289 to this issue. F5 has confirmed
that this issue exists in the products listed in the Applies to (see versions)
box, located in the upper-right corner of this article. For information about
releases, point releases, or hotfixes that resolve this issue, refer to the
following table.
+------------------+-----------------+----------------------------------------+
|Type of fix |Fixes introduced |Related articles |
| |in | |
+------------------+-----------------+----------------------------------------+
|Release |16.0.0 |K2200: Most recent versions of F5 |
| |15.1.1 |software |
+------------------+-----------------+----------------------------------------+
|Point release/ |14.1.2.5 |K9502: BIG-IP hotfix and point release |
|hotfix |13.1.3.4 |matrix |
+------------------+-----------------+----------------------------------------+
Security Advisory Recommended Actions
Workaround
To work around this issue, you can directly use the DNS over TCP vector (and
specify bad actor or attacked destination).
Supplemental Information
o K51812227: Understanding security advisory versioning
o K41942608: Overview of AskF5 security advisory articles
o K4602: Overview of the F5 security vulnerability response policy
o K4918: Overview of the F5 critical issue hotfix policy
o K9502: BIG-IP hotfix and point release matrix
o K13123: Managing BIG-IP product hotfixes (11.x - 16.x)
o K167: Downloading software and firmware from F5
o K9970: Subscribing to email notifications regarding F5 products
o K9957: Creating a custom RSS feed to view new and updated documents
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The University of Queensland
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