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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2019.0280 K21942600: A virtual server with a Client SSL profile may accept non-SSL traffic 31 January 2019 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: F5 BIG-IP Publisher: F5 Networks Operating System: Network Appliance Impact/Access: Unauthorised Access -- Remote/Unauthenticated Resolution: Patch/Upgrade Original Bulletin: https://support.f5.com/csp/article/K21942600 - --------------------------BEGIN INCLUDED TEXT-------------------- K21942600: A virtual server with a Client SSL profile may accept non-SSL traffic Security Advisory Original Publication Date: Jan 30, 2019 Applies to (see versions): o Product: BIG-IP o 13.1.1, 13.1.0, 13.0.1, 13.0.0 Security Advisory Description A Client SSL profile using a cipher group and an option that modifies supported ciphers (for example no-dtls or no-ssl) accepts plain text connections, in addition to correctly handling SSL traffic. This issue occurs when all of the following conditions are met: o A virtual server is configured with a Client SSL profile. o The Client SSL profile is configured to use a cipher group. o The Client SSL profile is also configured to modify the supported ciphers with an option enabled, such as No SSL, No TLS, or No DTLS. Important: The cipher group option was introduced in BIG-IP 13.0.0. Previous versions are not affected by this issue. Impact This behavior allows information normally sent over encrypted channels to be delivered over a clear text link. If client authentication is configured, clear text requests are successful, allowing an unauthenticated client to access resources that would otherwise require a valid client certificate. Symptoms As a result of this issue, you may encounter the following symptom: o An affected virtual server may process non-SSL (clear text) requests. Security Advisory Status F5 Product Development has assigned ID 743857 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 |None |None | +------------------+-----------------+----------------------------------------+ |Point release/ |13.1.1.4 |K9502: BIG-IP hotfix and point release | |hotfix | |matrix | +------------------+-----------------+----------------------------------------+ Security Advisory Recommended Actions Workaround To work around this issue, you can configure the affected Client SSL profile to use a cipher suite and specify a cipher string with the desired ciphers, rather than the Cipher Group and Options.. To do so, perform the following procedure: Impact of workaround: The impact of the suggested workaround will depend on the specific environment. F5 recommends testing any such changes during a maintenance window with consideration to the possible impact on your specific environment. 1. Log in to the Configuration utility. 2. Navigate to Local Traffic > Virtual Severs > Profiles > SSL > Client. 3. Select the affected Client SSL profile. 4. From the Configuration menu, select Advanced 5. In the Ciphers section, select Cipher Suites and enter the desired cipher string in the text field. 6. Click Update. 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 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. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBXFJwi2aOgq3Tt24GAQi3zBAAyF682MWtCsn/KwjcHFVPTq1UnE79IRLN n2BIwbcx6LlZFEschpD9OvqGxAB5cG4hGTaV7nPxxyc3ZJAnxZ44zK8P81NgPQeA UkpM2z7yC+FxsajPo4W4hDjh71x529b2IiXYESuSY7AWcOZ4O2YUTEVIEee437HP 0r85S9rHJiH48LPSujfvOIVM0ISugDEMBXFOfE0afMkDd78KzusEcJquD8apOFWe WkN3B9V3djJz6sV927yf6iZR74nzAHKgixiS0yHXvwoQ9tunTKOIy53ihmY/ck7e atIeBTcnhSYsdxg+FJfiZFcKnvH5QvGbZqfHimV0aZBE0Y21MDRe4ew3WuAHn2Mu 2RTDROo0GTh8CX0/a/wES8P9TZP66d6LbgexZRNHQMeXec+DP63p/pwPBsQfyH20 IABxE+cr24U3EKmqk0R8ZwYR3s+EP5MJFsHO/w1HzOoVwLHy9hFov2P4CtXMSgBu TgUTt7GuU0m5NgJNPmxgo+TwZUAfyi5LnTxd8cPExpbh+LHWXtqpQwoR2ltVQU/y HjXvwFS//qiaWMJnV/SvvU5QmyNxGc4PDSNCuHlmE839Cs12BHrqjKxoFlRoDX10 erBFSH9X2z1P9uIzZEuzsFLWpXwDd+qZrfhnRiOAzfT7hbD9UK/Ja1oGHjaJBPGl 3GWR8TVR5DQ= =uVwb -----END PGP SIGNATURE-----