Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.0069 USN-4679-1: Linux kernel vulnerabilities 7 January 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: kernel Publisher: Ubuntu Operating System: Ubuntu Impact/Access: Access Privileged Data -- Existing Account Denial of Service -- Existing Account Unauthorised Access -- Existing Account Reduced Security -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2020-28974 CVE-2020-27777 CVE-2020-27675 CVE-2020-25704 CVE-2020-25668 CVE-2020-25656 Reference: ESB-2020.4505 ESB-2020.4341 ESB-2020.4168 Original Bulletin: https://ubuntu.com/security/notices/USN-4679-1 - --------------------------BEGIN INCLUDED TEXT-------------------- USN-4679-1: Linux kernel vulnerabilities 06 January 2021 Several security issues were fixed in the Linux kernel. Releases o Ubuntu 20.04 LTS o Ubuntu 18.04 LTS Packages o linux - Linux kernel o linux-aws - Linux kernel for Amazon Web Services (AWS) systems o linux-aws-5.4 - Linux kernel for Amazon Web Services (AWS) systems o linux-azure - Linux kernel for Microsoft Azure Cloud systems o linux-azure-5.4 - Linux kernel for Microsoft Azure cloud systems o linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems o linux-gcp-5.4 - Linux kernel for Google Cloud Platform (GCP) systems o linux-gke-5.4 - Linux kernel for Google Container Engine (GKE) systems o linux-hwe-5.4 - Linux hardware enablement (HWE) kernel o linux-kvm - Linux kernel for cloud environments o linux-oracle - Linux kernel for Oracle Cloud systems o linux-oracle-5.4 - Linux kernel for Oracle Cloud systems o linux-raspi - Linux kernel for Raspberry Pi (V8) systems o linux-raspi-5.4 - Linux kernel for Raspberry Pi (V8) systems Details It was discovered that the console keyboard driver in the Linux kernel contained a race condition. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-25656) Minh Yuan discovered that the tty driver in the Linux kernel contained race conditions when handling fonts. A local attacker could possibly use this to expose sensitive information (kernel memory). (CVE-2020-25668) Kiyin () discovered that the perf subsystem in the Linux kernel did not properly deallocate memory in some situations. A privileged attacker could use this to cause a denial of service (kernel memory exhaustion). (CVE-2020-25704) Jinoh Kang discovered that the Xen event channel infrastructure in the Linux kernel contained a race condition. An attacker in guest could possibly use this to cause a denial of service (dom0 crash). (CVE-2020-27675) Daniel Axtens discovered that PowerPC RTAS implementation in the Linux kernel did not properly restrict memory accesses in some situations. A privileged local attacker could use this to arbitrarily modify kernel memory, potentially bypassing kernel lockdown restrictions. (CVE-2020-27777) Minh Yuan discovered that the framebuffer console driver in the Linux kernel did not properly handle fonts in some conditions. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory). (CVE-2020-28974) Update instructions The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 o linux-image-5.4.0-1026-raspi - 5.4.0-1026.29 o linux-image-5.4.0-1031-kvm - 5.4.0-1031.32 o linux-image-5.4.0-1033-gcp - 5.4.0-1033.35 o linux-image-5.4.0-1034-aws - 5.4.0-1034.35 o linux-image-5.4.0-1034-oracle - 5.4.0-1034.36 o linux-image-5.4.0-1035-azure - 5.4.0-1035.36 o linux-image-5.4.0-59-generic - 5.4.0-59.65 o linux-image-5.4.0-59-generic-lpae - 5.4.0-59.65 o linux-image-5.4.0-59-lowlatency - 5.4.0-59.65 o linux-image-aws - 5.4.0.1034.35 o linux-image-azure - 5.4.0.1035.33 o linux-image-gcp - 5.4.0.1033.42 o linux-image-generic - 5.4.0.59.62 o linux-image-generic-lpae - 5.4.0.59.62 o linux-image-kvm - 5.4.0.1031.29 o linux-image-lowlatency - 5.4.0.59.62 o linux-image-oem - 5.4.0.59.62 o linux-image-oem-osp1 - 5.4.0.59.62 o linux-image-oracle - 5.4.0.1034.31 o linux-image-raspi - 5.4.0.1026.61 o linux-image-raspi2 - 5.4.0.1026.61 o linux-image-virtual - 5.4.0.59.62 Ubuntu 18.04 o linux-image-5.4.0-1026-raspi - 5.4.0-1026.29~18.04.1 o linux-image-5.4.0-1033-gcp - 5.4.0-1033.35~18.04.1 o linux-image-5.4.0-1033-gke - 5.4.0-1033.35~18.04.1 o linux-image-5.4.0-1034-aws - 5.4.0-1034.35~18.04.1 o linux-image-5.4.0-1034-oracle - 5.4.0-1034.36~18.04.1 o linux-image-5.4.0-1035-azure - 5.4.0-1035.36~18.04.1 o linux-image-5.4.0-59-generic - 5.4.0-59.65~18.04.1 o linux-image-5.4.0-59-generic-lpae - 5.4.0-59.65~18.04.1 o linux-image-5.4.0-59-lowlatency - 5.4.0-59.65~18.04.1 o linux-image-aws - 5.4.0.1034.19 o linux-image-azure - 5.4.0.1035.17 o linux-image-gcp - 5.4.0.1033.21 o linux-image-generic-hwe-18.04 - 5.4.0.59.65~18.04.54 o linux-image-generic-lpae-hwe-18.04 - 5.4.0.59.65~18.04.54 o linux-image-gke-5.4 - 5.4.0.1033.35~18.04.2 o linux-image-lowlatency-hwe-18.04 - 5.4.0.59.65~18.04.54 o linux-image-oem - 5.4.0.59.65~18.04.54 o linux-image-oem-osp1 - 5.4.0.59.65~18.04.54 o linux-image-oracle - 5.4.0.1034.36~18.04.18 o linux-image-raspi-hwe-18.04 - 5.4.0.1026.30 o linux-image-snapdragon-hwe-18.04 - 5.4.0.59.65~18.04.54 o linux-image-virtual-hwe-18.04 - 5.4.0.59.65~18.04.54 After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well. References o CVE-2020-28974 o CVE-2020-25656 o CVE-2020-25704 o CVE-2020-27675 o CVE-2020-27777 o CVE-2020-25668 Related notices o USN-4681-1 : linux-image-powerpc64-smp, linux-image-generic-lpae-lts-xenial, linux-image-4.4.0-1143-raspi2, linux-image-4.4.0-198-powerpc64-smp, linux-image-4.4.0-1147-snapdragon, linux-lts-xenial, linux-snapdragon, linux, linux-image-4.4.0-198-powerpc64-emb, linux-image-virtual-lts-xenial, linux-image-4.4.0-198-powerpc-smp, linux-image-lowlatency, linux-kvm, linux-image-4.4.0-1083-aws, linux-image-4.4.0-198-powerpc-e500mc, linux-image-snapdragon, linux-raspi2, linux-image-kvm, linux-image-powerpc-smp-lts-xenial, linux-image-powerpc-e500mc, linux-image-powerpc-smp, linux-image-virtual, linux-image-lowlatency-lts-xenial, linux-image-4.4.0-198-generic-lpae, linux-image-generic-lts-xenial, linux-image-4.4.0-1119-aws, linux-image-4.4.0-198-lowlatency, linux-image-raspi2, linux-image-generic-lpae, linux-image-powerpc-e500mc-lts-xenial, linux-image-powerpc64-smp-lts-xenial, linux-aws, linux-image-4.4.0-198-generic, linux-image-generic, linux-image-powerpc64-emb, linux-image-powerpc64-emb-lts-xenial, linux-image-aws, linux-image-4.4.0-1085-kvm o USN-4680-1 : linux-image-4.15.0-1091-aws, linux-image-4.15.0-1077-raspi2, linux-image-powerpc64-smp, linux-image-oracle-lts-18.04, linux-image-4.15.0-1094-snapdragon, linux-gcp-4.15, linux-snapdragon, linux, linux-gcp, linux-image-azure, linux-azure-4.15, linux-image-4.15.0-1077-gke, linux-image-generic-lpae-hwe-16.04, linux-image-4.15.0-1091-gcp, linux-image-4.15.0-129-generic-lpae, linux-gke-4.15, linux-image-4.15.0-1082-kvm, linux-kvm, linux-image-gke, linux-image-4.15.0-1062-oracle, linux-image-snapdragon, linux-image-gcp-lts-18.04, linux-raspi2, linux-image-4.15.0-129-generic, linux-image-aws-hwe, linux-image-oracle, linux-image-kvm, linux-image-4.15.0-1103-azure, linux-image-oem, linux-image-powerpc-e500mc, linux-image-powerpc-smp, linux-image-virtual, linux-image-virtual-hwe-16.04, linux-image-aws-lts-18.04, linux-image-raspi2, linux-image-azure-lts-18.04, linux-image-generic-hwe-16.04, linux-image-generic-lpae, linux-oracle, linux-aws, linux-azure, linux-hwe, linux-image-gcp, linux-image-generic, linux-image-gke-4.15, linux-image-lowlatency-hwe-16.04, linux-image-powerpc64-emb, linux-aws-hwe, linux-image-4.15.0-129-lowlatency, linux-image-lowlatency - --------------------------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 iQIVAwUBX/ZhFuNLKJtyKPYoAQjL2w//VQZHoyW1AIxHZ9uWey4o6SyGYeQurJnc /Xx8QEfU9C6iEeBJhT8ngdsLc8+OyjYA6DC/CIKgVIxOzpYC3MUuUOY3BBfYjx2N aZxLjBt4+Ls6jRSdyU+dcZ8yDxwkbAWIW6IEGohTjJCDDQH0cR8iyVhp05nq+DQb W/3lcjKNDek2dVuBN5Ftr9mmVGT2C5vzlvWklf/EVpIoPEz/C0GFwJ2li6SQ1P3B HNHxfJHapIb2L2dVQP9rnl8yRqyldRLLJptJ8xhox8JysjwQyERffeYYUP9pjKlP 1X2lxZBdE8hnIiS0XVu2qazQD6mwRNUQG6Y6xfRo/9y5nRaeuMMkAsgReCudSO1v RnzhlQuUPlp4vv6R4l9chA6opXmiV5+mt2VYrz0xBXifu5V4X135EYTDv+Oo41di g0C9ifdRWeM4sCJ5XpcUL3OdJc31C+b2zO3c6Hf3N1ZFSk808KwbnAdWAU5lZmFk j3kFEF3eWPY/bAKTHf852v2LCKTwDxJXATf9n/sMM6grur+vfv5nUaY1mno17nC2 O88oRSBf/9eRU5ohXcbCGEtTBPHEAbiQjKrNdb5dyR1xX2cjQsSxWSLhjAyG1fBW hAbTH5J1K+WyUdj7NgCb0p8wyYfNj5YRBi5ha2ZMtgDWESW4AH6TCHQrhmKBnAQT 4gNAISYFBTk= =V7rj -----END PGP SIGNATURE-----