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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.1842.5 BIG-IP & BIG-IQ BIND vulnerability CVE-2020-8617 25 June 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: BIG-IP BIG-IQ Publisher: F5 Networks Operating System: Network Appliance Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2020-8617 Reference: ESB-2020.1820 ESB-2020.1778 ESB-2020.1777.2 ESB-2020.1771 Original Bulletin: https://support.f5.com/csp/article/K05544642 Revision History: June 25 2020: Vendor released minor update June 19 2020: Vendor updated Product Status Advisory table June 12 2020: Fixes introduced for BIG-IP June 1 2020: Vendor published mitigation information May 25 2020: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- K05544642:BIND vulnerability CVE-2020-8617 Security Advisory Original Publication Date: 21 May, 2020 Latest Publication Date: 24 Jun, 2020 Security Advisory Description Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results. (CVE-2020-8617) Impact An attacker can exploit this vulnerability to trigger an assertion failure, resulting in a denial of service to clients. Security Advisory Status F5 Product Development has assigned IDs 909237 (BIG-IP) and 909237-8 (BIG-IQ) to this vulnerability. To determine if your product and version have been evaluated for this vulnerability, refer to the Applies to (see versions) box. To determine if your release is known to be vulnerable, the components or features that are affected by the vulnerability, and for information about releases, point releases, or hotfixes that address the vulnerability, refer to the following table. For more information about security advisory versioning, refer to K51812227: Understanding Security Advisory versioning. +-------------------+------+----------+----------+----------+------+----------+ | | |Versions |Fixes | |CVSSv3|Vulnerable| |Product |Branch|known to |introduced|Severity |score^|component | | | |be |in | |1 |or feature| | | |vulnerable| | | | | +-------------------+------+----------+----------+----------+------+----------+ | |15.x |15.0.0 - |15.1.0.4 | | | | | | |15.1.0 | | | | | | +------+----------+----------+ | | | | |14.x |14.1.0 - |14.1.2.6 | | | | |BIG-IP (LTM, AAM, | |14.1.2 | | | | | |AFM, Analytics, +------+----------+----------+ | | | |APM, ASM, DNS, FPS,|13.x |13.1.0 - |13.1.3.4 |High |7.5 |BIND | |GTM, Link | |13.1.3 | | | | | |Controller, PEM) +------+----------+----------+ | | | | |12.x |12.1.0 - |None | | | | | | |12.1.5 | | | | | | +------+----------+----------+ | | | | |11.x |11.6.1 - |11.6.5.2 | | | | | | |11.6.5 | | | | | +-------------------+------+----------+----------+----------+------+----------+ | |7.x |7.0.0 - |None | | | | | | |7.1.0 | | | | | | +------+----------+----------+ | | | |BIG-IQ Centralized |6.x |6.0.0 - |None |High |7.5 |BIND | |Management | |6.1.0 | | | | | | +------+----------+----------+ | | | | |5.x |5.3.0 - |None | | | | | | |5.4.0 | | | | | +-------------------+------+----------+----------+----------+------+----------+ |Traffix SDC |5.x |None |Not |Not |None |None | | | | |applicable|vulnerable| | | +-------------------+------+----------+----------+----------+------+----------+ ^1The CVSSv3 score link takes you to a resource outside of AskF5, and it is possible that the document may be removed without our knowledge. Security Advisory Recommended Actions If you are running a version listed in the Versions known to be vulnerable column, you can eliminate this vulnerability by upgrading to a version listed in the Fixes introduced in column. If the table lists only an older version than what you are currently running, or does not list a non-vulnerable version, then no upgrade candidate currently exists. Mitigation The following mitigation options are available for the BIG-IP and BIG-IQ systems: o BIG-IP o BIG-IQ BIG-IP To mitigate this vulnerability for the BIG-IP system, perform the following actions: o When there is no requirement to use the BIG-IP DNS service, you should secure the self IP addresses on the BIG-IP system by using the port lockdown feature to deny access to DNS services on the system. To do so, refer to the Using the Configuration utility to modify port lockdown settings for a specific self IP procedure in K17333: Overview of port lockdown behavior (12.x - 15.x). The management IP address of the BIG-IP system does not respond to DNS queries. BIG-IP DNS, BIG-IP GTM, and Link Controller To mitigate this vulnerability, you can configure the DNS profile to not forward queries to BIND by setting Use BIND Server on BIG-IP to Disabled. For queries that do not need to be processed further in BIND, if there is no pool assigned to the Virtual Server processing DNS request, set Unhandled Query Actions to any setting other than Allow (for example, Drop or Hint). For Virtual Server processing DNS requests assigned with a pool of DNS Servers or configured for DNS Caching , set Unhandled Query Actions to Allow. Setting Unhandled Query Actions to Allow will allow further processing of the DNS requests to the pool of DNS Servers. To do so, perform the following procedure: Important: Disabling the BIND server can affect DNS configurations that use BIND as a fallback method (return to DNS) for resolution. 1. Log in to the Configuration utility. 2. Go to Local Traffic > Profiles > Services > DNS. 3. Select the applicable DNS profile. 4. For Use BIND Server on BIG-IP, select Disabled. 5. Set Unhandled Query Actions: If you have a virtual server which is processing DNS requests assigned with a pool of DNS servers or configured for DNS caching, for Unhandled Query Actions select Allow. If there is no pool assigned to the virtual server, for Unhandled Query Actions, select a setting other than Allow. For example, select Drop or Hint. 6. Select Update. BIG-IQ When there is no requirement to use the BIG-IP DNS service, you should secure the self IP addresses on the BIG-IQ system by using the port lockdown feature to deny access to DNS services on the system. To do so, refer to K39403510: Managing the port lockdown configuration on the BIG-IQ system. The management IP address of the BIG-IQ system does not respond to DNS queries. 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 - 15.x) o K15106: Managing BIG-IQ product hotfixes o K15113: BIG-IQ hotfix and point release matrix 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 - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. 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