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AUSCERT External Security Bulletin Redistribution
ESB-2021.2216
USN-4997-1: Linux kernel vulnerabilities
23 June 2021
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AusCERT Security Bulletin Summary
---------------------------------
Product: kernel
Publisher: Ubuntu
Operating System: Ubuntu
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Root Compromise -- Existing Account
Increased Privileges -- Existing Account
Denial of Service -- Remote/Unauthenticated
Access Confidential Data -- Remote with User Interaction
Reduced Security -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2021-33200 CVE-2021-33034 CVE-2021-32399
CVE-2021-31829 CVE-2021-31440 CVE-2021-23134
CVE-2021-23133 CVE-2021-3609 CVE-2021-3543
CVE-2021-3506 CVE-2020-26147 CVE-2020-26145
CVE-2020-26141 CVE-2020-26139 CVE-2020-24588
CVE-2020-24587 CVE-2020-24586
Reference: ESB-2021.2184
ESB-2021.2136
ESB-2021.2079
ESB-2021.1945
Original Bulletin:
https://ubuntu.com/security/notices/USN-4997-1
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USN-4997-1: Linux kernel vulnerabilities
23 June 2021
Several security issues were fixed in the Linux kernel.
Releases
o Ubuntu 21.04
Packages
o linux - Linux kernel
o linux-aws - Linux kernel for Amazon Web Services (AWS) systems
o linux-azure - Linux kernel for Microsoft Azure Cloud systems
o linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
o linux-oracle - Linux kernel for Oracle Cloud systems
o linux-raspi - Linux kernel for Raspberry Pi (V8) systems
Details
Norbert Slusarek discovered a race condition in the CAN BCM networking
protocol of the Linux kernel leading to multiple use-after-free
vulnerabilities. A local attacker could use this issue to execute arbitrary
code. ( CVE-2021-3609 )
Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly enforce limits for pointer operations. A local attacker
could use this to cause a denial of service (system crash) or possibly
execute arbitrary code. ( CVE-2021-33200 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation did
not properly clear received fragments from memory in some situations. A
physically proximate attacker could possibly use this issue to inject
packets or expose sensitive information. ( CVE-2020-24586 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation
incorrectly handled encrypted fragments. A physically proximate attacker
could possibly use this issue to decrypt fragments. ( CVE-2020-24587 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation
incorrectly handled certain malformed frames. If a user were tricked into
connecting to a malicious server, a physically proximate attacker could use
this issue to inject packets. ( CVE-2020-24588 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation
incorrectly handled EAPOL frames from unauthenticated senders. A physically
proximate attacker could inject malicious packets to cause a denial of
service (system crash). ( CVE-2020-26139 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation did
not properly verify certain fragmented frames. A physically proximate
attacker could possibly use this issue to inject or decrypt packets.
( CVE-2020-26141 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation
accepted plaintext fragments in certain situations. A physically proximate
attacker could use this issue to inject packets. ( CVE-2020-26145 )
Mathy Vanhoef discovered that the Linux kernel's WiFi implementation could
reassemble mixed encrypted and plaintext fragments. A physically proximate
attacker could possibly use this issue to inject packets or exfiltrate
selected fragments. ( CVE-2020-26147 )
Or Cohen discovered that the SCTP implementation in the Linux kernel
contained a race condition in some situations, leading to a use-after-free
condition. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. ( CVE-2021-23133 )
Or Cohen and Nadav Markus discovered a use-after-free vulnerability in the
nfc implementation in the Linux kernel. A privileged local attacker could
use this issue to cause a denial of service (system crash) or possibly
execute arbitrary code. ( CVE-2021-23134 )
Manfred Paul discovered that the extended Berkeley Packet Filter (eBPF)
implementation in the Linux kernel contained an out-of-bounds
vulnerability. A local attacker could use this issue to execute arbitrary
code. ( CVE-2021-31440 )
Piotr Krysiuk discovered that the eBPF implementation in the Linux kernel
did not properly prevent speculative loads in certain situations. A local
attacker could use this to expose sensitive information (kernel memory).
( CVE-2021-31829 )
It was discovered that a race condition in the kernel Bluetooth subsystem
could lead to use-after-free of slab objects. An attacker could use this
issue to possibly execute arbitrary code. ( CVE-2021-32399 )
It was discovered that a use-after-free existed in the Bluetooth HCI driver
of the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. ( CVE-2021-33034 )
It was discovered that an out-of-bounds (OOB) memory access flaw existed in
the f2fs module of the Linux kernel. A local attacker could use this issue
to cause a denial of service (system crash). ( CVE-2021-3506 )
Mathias Krause discovered that a null pointer dereference existed in the
Nitro Enclaves kernel driver of the Linux kernel. A local attacker could
use this issue to cause a denial of service or possibly execute arbitrary
code. ( CVE-2021-3543 )
Update instructions
The problem can be corrected by updating your system to the following package
versions:
Ubuntu 21.04
o linux-image-5.11.0-1012-raspi - 5.11.0-1012.13
o linux-image-5.11.0-1010-oracle - 5.11.0-1010.10
o linux-image-5.11.0-22-generic - 5.11.0-22.23
o linux-image-oracle - 5.11.0.1010.10
o linux-image-azure - 5.11.0.1009.9
o linux-image-5.11.0-22-generic-lpae - 5.11.0-22.23
o linux-image-raspi-nolpae - 5.11.0.1012.10
o linux-image-5.11.0-1009-azure - 5.11.0-1009.9
o linux-image-5.11.0-22-lowlatency - 5.11.0-22.23
o linux-image-virtual - 5.11.0.22.23
o linux-image-generic - 5.11.0.22.23
o linux-image-raspi - 5.11.0.1012.10
o linux-image-gke - 5.11.0.1011.11
o linux-image-generic-64k - 5.11.0.22.23
o linux-image-5.11.0-22-generic-64k - 5.11.0-22.23
o linux-image-5.11.0-1012-raspi-nolpae - 5.11.0-1012.13
o linux-image-5.11.0-1011-gcp - 5.11.0-1011.12
o linux-image-aws - 5.11.0.1011.11
o linux-image-5.11.0-1011-aws - 5.11.0-1011.11
o linux-image-generic-lpae - 5.11.0.22.23
o linux-image-gcp - 5.11.0.1011.11
o linux-image-lowlatency - 5.11.0.22.23
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-2021-23134
o CVE-2021-3506
o CVE-2020-24586
o CVE-2020-24587
o CVE-2021-31440
o CVE-2021-33200
o CVE-2021-31829
o CVE-2021-32399
o CVE-2020-24588
o CVE-2020-26141
o CVE-2021-33034
o CVE-2020-26145
o CVE-2020-26147
o CVE-2021-3609
o CVE-2020-26139
o CVE-2021-23133
o CVE-2021-3543
Related notices
o USN-4983-1 : linux-image-oem-20.04-edge, linux-oem-5.10,
linux-image-oem-20.04b, linux-image-5.10.0-1029-oem, linux-image-oem-20.04
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