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AUSCERT External Security Bulletin Redistribution
ESB-2020.2864.2
USN-4465-1: linux kernel vulnerabilities
24 August 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: kernel
Publisher: Ubuntu
Operating System: Ubuntu
Impact/Access: Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2020-15393 CVE-2020-12771 CVE-2020-12655
Reference: ESB-2020.2842
ESB-2020.2532
Original Bulletin:
https://usn.ubuntu.com/4465-1/
Revision History: August 24 2020: Fixed packages list has been updated
August 20 2020: Initial Release
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USN-4465-1: linux kernel vulnerabilities
23 August 2020
Several security issues were fixed in the Linux kernel.
Releases
o Ubuntu 18.04 LTS
Packages
o linux-aws-5.3 - Linux kernel for Amazon Web Services (AWS) systems
o linux-azure-5.3 - Linux kernel for microsoft azure cloud systems
o linux-gke-5.3 - Linux kernel for Google Container Engine (GKE) systems
o linux-hwe - Linux hardware enablement (HWE) kernel
Details
It was discovered that the XFS file system implementation in the Linux
kernel did not properly validate meta data in some circumstances. An
attacker could use this to construct a malicious XFS image that, when
mounted, could cause a denial of service. (CVE-2020-12655)
It was discovered that the bcache subsystem in the Linux kernel did not
properly release a lock in some error conditions. A local attacker could
possibly use this to cause a denial of service. (CVE-2020-12771)
Kyungtae Kim discovered that the USB testing driver in the Linux kernel did
not properly deallocate memory on disconnect events. A physically proximate
attacker could use this to cause a denial of service (memory exhaustion).
(CVE-2020-15393)
Update instructions
The problem can be corrected by updating your system to the following package
versions:
Ubuntu 18.04
o linux-image-5.3.0-1033-aws - 5.3.0-1033.35
o linux-image-5.3.0-1033-gke - 5.3.0-1033.35
o linux-image-5.3.0-1035-azure - 5.3.0-1035.36
o linux-image-5.3.0-65-generic - 5.3.0-65.59
o linux-image-5.3.0-65-lowlatency - 5.3.0-65.59
o linux-image-aws - 5.3.0.1033.32
o linux-image-azure - 5.3.0.1035.31
o linux-image-gke-5.3 - 5.3.0.1033.18
o linux-image-gkeop-5.3 - 5.3.0.65.121
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-2020-12655
o CVE-2020-12771
o CVE-2020-15393
o CVE-2020-24394
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