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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2022.3377.2 K36462841: Linux kernel vulnerability CVE-2018-18281 13 July 2022 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: BIG-IP BIG-IQ Centralized Management F5OS-C Traffix SDC Publisher: F5 Networks Operating System: Network Appliance Resolution: Patch/Upgrade CVE Names: CVE-2018-18281 Original Bulletin: https://support.f5.com/csp/article/K36462841 Comment: CVSS (Max): 7.8 CVE-2018-18281 (CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H) CVSS Source: F5 Networks Calculator: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H Revision History: July 13 2022: Significant updates to Vendor bulletin July 11 2022: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- K36462841: Linux kernel vulnerability CVE-2018-18281 Original Publication Date: 09 Jul, 2022 Latest Publication Date: 13 Jul, 2022 Security Advisory Description Since Linux kernel version 3.2, the mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused. This is fixed in the following kernel versions: 4.9.135, 4.14.78, 4.18.16, 4.19. (CVE-2018-18281) Impact An attacker may be able to overflow temporary memory resources resulting in improper access to physical memory pages or denial-of-service (DoS). Security Advisory Status F5 Product Development has assigned IDs 1051797 (BIG-IP) and 1051797-6 (BIG-IQ) to this vulnerability. This issue has been classified as CWE-459: Incomplete Cleanup. 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 Applies to (see versions) box of this article 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 | +------------+------+--------------+----------+----------+------+-------------+ | |17.x |None |17.0.0 | | | | | +------+--------------+----------+ | | | | |16.x |16.1.0 - |16.1.3 | | | | | | |16.1.2 |16.1.2.2 | | | | | +------+--------------+----------+ | | | |BIG-IP (all |15.x |15.1.0 - |15.1.6 | | | | |modules) | |15.1.5 |15.1.5.1 |High |7.8 |Linux kernel | | +------+--------------+----------+ | | | | |14.x |14.1.0 - |14.1.5 | | | | | | |14.1.4 |14.1.4.6 | | | | | +------+--------------+----------+ | | | | |13.x |13.1.0 - |13.1.5 | | | | | | |13.1.4 | | | | | +------------+------+--------------+----------+----------+------+-------------+ |BIG-IP SPK |1.x |1.5.0 |Not |Not |None |None | | | | |applicable|vulnerable| | | +------------+------+--------------+----------+----------+------+-------------+ |BIG-IQ |8.x |8.0.0 - 8.2.0 |None | | | | |Centralized +------+--------------+----------+High |7.8 |Linux kernel | |Management |7.x |7.0.0 - 7.1.0 |None | | | | +------------+------+--------------+----------+----------+------+-------------+ |F5OS-A |1.x |None |Not |Not |None |None | | | | |applicable|vulnerable| | | +------------+------+--------------+----------+----------+------+-------------+ | | |1.3.0 | | | | | |F5OS-C |1.x |1.2.0 - 1.2.2 |1.3.1 |High |7.8 |Linux kernel | | | |1.1.0 - 1.1.4 | | | | | +------------+------+--------------+----------+----------+------+-------------+ |Traffix SDC |5.x |None |Not |Not |None |None | | | | |applicable|vulnerable| | | +------------+------+--------------+----------+----------+------+-------------+ ^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 As this attack is conducted by legitimate, authenticated users, there is no viable mitigation that also allows users access to the BIG-IP or BIG-IQ system. The only mitigation is to remove access for users who are not completely trusted. Until it is possible to install a fixed version, you can use the following sections as temporary mitigations. These mitigations restrict access to the BIG-IP or BIG-IQ command line through SSH to only trusted networks or devices, thereby limiting the attack surface. o Block SSH access through self IP addresses o Block SSH access through the management interface Block SSH access through self IP addresses You can block all access to the command line through SSH of your BIG-IP or BIG-IQ 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 block access to SSH. By default, the SSH service listens on TCP port 22. Note: Performing this action prevents all access to SSH using the self IP address. These changes may also impact other services. 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 - 17.x) o K39403510: Managing the port lockdown configuration on the BIG-IQ system o K13092: Overview of securing access to the BIG-IP system If you must expose port 22 on your self IP addresses and want to restrict access to specific IP ranges, you may consider using the packet filtering functionality built into the BIG-IP system. For more information, refer to the following article: o K13383: Configuring CIDR Network Addresses for the BIG-IP packet filter For BIG-IQ self IP addresses where port 22 is exposed, use an external packet filtering device such as BIG-IP AFM. Block SSH access through the management interface To mitigate this vulnerability for affected F5 products, you should restrict management access to F5 products to only trusted users and devices over a secure network. For more information about securing access to BIG-IP and BIG-IQ systems, refer to the following articles: o K13092: Overview of securing access to the BIG-IP system o K46122561: Restricting access to the BIG-IP management interface using network firewall rules o K92748202: Restricting access to the BIG-IQ 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 - 17.x) o K15106: Managing BIG-IQ product hotfixes o K15113: BIG-IQ hotfix and point release matrix 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). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: https://auscert.org.au/gpg-key/ iQIVAwUBYs5k0skNZI30y1K9AQhydg//bJNnO8qSadOneEFjas0sMcyJBOZ2aYI+ D9cGuHpOa82IAr3c1JRzwip3qUDCAtm40S8B9N3PFwh/lsB+m4PYerW4hP3Hii40 ZXVLtoinLSJk21fuawWewVtXA9s8Dkhgh9NxkZ3+aZW5Xu/m0SNvO57bo2d78fn7 NHmUIcU8wQKv2bGqXvzJF23LmkoXsUbPMyKnAkykQXKEH57FJS9BDYk2CF7zpAiN l7ipqbtuuzwgWKxLYQKCewKZDBJT6V2kXA7L42wuuMfXrJsIKkuzO6JlimzhMtnj QCTn61ELGVReSC0xSMtKmL9mGKReceAJWdQCt1sgdLy4Oi36w968nS9Rf7Jv1I39 y8LGJtJ/iJv6fO4LjsENWBLBTq5tCosvvxbXBtE8u+GNDGmO7ZB6asqMqbcBwQ2a FVk7WfH5v3ZIoEDC2sDv2o87giDuxMgtfNVTQGNjakJ5x0j59rnKu6tHr8/3aDRn jSpLWGekPKJywWnedXWvlIPQiougu5AR93xKLYh42VInKmUItF61KU1jIw2x8fL/ 9tGpWoAc0QnUBd9T849cY3NKVKkXijQKnECqSdS+lXMhh9+GSKmHUwYDHUOWhdJ+ yqAYL0MZrda7E2uX/nOA883nW4yZ88jGvrKQvm/FvcfkcMjYUd9RnfJMPF1jsRom ob/npBh1wb8= =HXkI -----END PGP SIGNATURE-----