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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.2664 Apache Tomcat vulnerability CVE-2021-33037 9 August 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: F5 BIG-IP F5 Traffix SDC Publisher: F5 Networks Operating System: Network Appliance Impact/Access: Reduced Security -- Remote/Unauthenticated Unauthorised Access -- Remote/Unauthenticated Resolution: Mitigation CVE Names: CVE-2021-33037 Reference: ESB-2021.2647 ESB-2021.2359 Original Bulletin: https://support.f5.com/csp/article/K32469285 - --------------------------BEGIN INCLUDED TEXT-------------------- K32469285: Apache Tomcat vulnerability CVE-2021-33037 Original Publication Date: 07 Aug, 2021 Security Advisory Description Apache Tomcat 10.0.0-M1 to 10.0.6, 9.0.0.M1 to 9.0.46 and 8.5.0 to 8.5.66 did not correctly parse the HTTP transfer-encoding request header in some circumstances leading to the possibility to request smuggling when used with a reverse proxy. Specifically: - Tomcat incorrectly ignored the transfer encoding header if the client declared it would only accept an HTTP/1.0 response; - Tomcat honoured the identify encoding; and - Tomcat did not ensure that, if present, the chunked encoding was the final encoding. (CVE-2021-33037) Impact A remote attacker may be able to bypass security controls and gain access to restricted content, such as a site administration page. Security Advisory Status F5 Product Development has assigned ID 1039109 (BIG-IP) and SDC-1292 (Traffix) 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. Note: After a fix is introduced for a given minor branch, that fix applies to all subsequent maintenance and point releases for that branch, and no additional fixes for that branch will be listed in the table. For example, when a fix is introduced in 14.1.2.3, the fix also applies to 14.1.2.4, and all later 14.1.x releases (14.1.3.x., 14.1.4.x). For more information, refer to K51812227: Understanding security advisory versioning. Additionally, software versions preceding those listed in the following table have reached the End of Technical Support (EoTS) phase of their lifecycle and are no longer evaluated for security issues. For more information, refer to the Security hotfixes section of K4602: Overview of the F5 security vulnerability response policy. +------------+------+--------------+----------+----------+------+-------------+ | | |Versions known|Fixes | |CVSSv3|Vulnerable | |Product |Branch|to be |introduced|Severity |score^|component or | | | |vulnerable^1 |in | |2 |feature | +------------+------+--------------+----------+----------+------+-------------+ | |16.x |16.0.0 - |None | | | | | | |16.1.0 | | | | | | +------+--------------+----------+ | | | | |15.x |15.1.0 - |None | | | | | | |15.1.3 | | | | | | +------+--------------+----------+ | | | | |14.x |14.1.0 - |None | | | | |BIG-IP (all | |14.1.4 | | | | | |modules) +------+--------------+----------+Medium |4.3 |Apache Tomcat| | |13.x |13.1.0 - |None | | | | | | |13.1.4 | | | | | | +------+--------------+----------+ | | | | |12.x |12.1.0 - |None | | | | | | |12.1.6 | | | | | | +------+--------------+----------+ | | | | |11.x |11.6.1 - |None | | | | | | |11.6.5 | | | | | +------------+------+--------------+----------+----------+------+-------------+ | |8.x |None |Not | | | | | | | |applicable| | | | |BIG-IQ +------+--------------+----------+ | | | |Centralized |7.x |None |Not |Not |None |None | |Management | | |applicable|vulnerable| | | | +------+--------------+----------+ | | | | |6.x |None |Not | | | | | | | |applicable| | | | +------------+------+--------------+----------+----------+------+-------------+ |F5OS |1.x |None |Not |Not |None |None | | | | |applicable|vulnerable| | | +------------+------+--------------+----------+----------+------+-------------+ |Traffix SDC |5.x |5.1.0 - 5.2.0 |None |Medium |4.3 |Apache Tomcat| +------------+------+--------------+----------+----------+------+-------------+ ^1F5 evaluates only software versions that have not yet reached the End of Technical Support (EoTS) phase of their lifecycle. ^2The CVSSv3 score link takes you to a resource outside of AskF5, and it is possible that the document may be removed without our knowledge. Recommended Actions If you are running a version listed in the Versions known to be vulnerable column, you can eliminate this vulnerability by installing a version listed in the Fixes introduced in column. If the Fixes introduced in column does not list a version for your branch, then no update candidate currently exists for that branch and F5 recommends upgrading to a version with the fix (refer to the table). If the Fixes introduced in column lists a version prior to the one you are running, in the same branch, then your version should have the fix. Mitigation Until it is possible to install a fixed version, you can use the following sections as temporary mitigations. These mitigations restrict access to the Configuration utility to only trusted networks or devices, thereby limiting the attack surface. o Block Configuration utility access through self IP addresses o Block Configuration utility access through the management interface Block Configuration utility access through self IP addresses You can block all access to the Configuration utility of your BIG-IP system using self IP addresses. To do so, you can change the Port Lockdown setting to Allow None for each self IP address on the system. If you must open any ports, you should use the Allow Custom option, taking care to disallow access to the Configuration utility. By default, the Configuration utility listens on TCP port 443. If you modified the default port, ensure that you block access to the alternate port you configured. Note: Performing this action prevents all access to the Configuration utility and iControl REST using the self IP address. These changes may also impact other services, including breaking high availability (HA) configurations. Before you make changes to the configuration of your self IP addresses, F5 strongly recommends that you refer to the following articles: o K17333: Overview of port lockdown behavior (12.x - 16.x) o K13092: Overview of securing access to the BIG-IP system o K31003634: The Configuration utility of the Single-NIC BIG-IP Virtual Edition now defaults to TCP port 8443 o K51358480: The single-NIC BIG-IP VE may erroneously revert to the default management httpd port after a configuration reload If you must expose port 443 on your self IP addresses and want to restrict access to specific IP ranges, you may consider using the packet filtering functionality built in to the BIG-IP system. For more information, refer to the following article: o K13383: Configuring CIDR Network Addresses for the BIG-IP packet filter Block Configuration utility access through the management interface To mitigate this vulnerability for affected F5 products, you should restrict management access to only trusted users and devices to F5 products over a secure network. For more information about securing access to BIG-IP systems, refer to the following articles: o K13309: Restricting access to the Configuration utility by source IP address (11.x - 16.x) o K13092: Overview of securing access to the BIG-IP system o K46122561: Restricting access to the management interface using network firewall rules Supplemental Information o K41942608: Overview of security advisory articles o K4602: Overview of the F5 security vulnerability response policy o K4918: Overview of the F5 critical issue hotfix policy o K8986: F5 software lifecycle policy o K9502: BIG-IP hotfix and point release matrix o K13123: Managing BIG-IP product hotfixes (11.x - 16.x) o K48955220: Installing an OPSWAT Endpoint Security update on BIG-IP APM systems (11.4.x and later) 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). 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