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Episode 119
Overview
This week we cover security updates for the Linux kernel, PolicyKit, Intel
Microcode and more, plus we look at a report of an apparent malicious snap
in the Snap Store and some of the mechanics behind snap confinement.
This week in Ubuntu Security Updates
42 unique CVEs addressed
[USN-4979-1] Linux kernel vulnerabilities [01:04]
mounting an malicious ext4 image -> crash (DoS)
[USN-4982-1] Linux kernel vulnerabilities [02:23]
[USN-4984-1] Linux kernel vulnerabilities [02:39]
[USN-4977-1] Linux kernel vulnerabilities
connection between two NFC devices
[USN-4983-1] Linux kernel (OEM) vulnerabilities [03:32]
programs which could cause speculative loads -> info leak
[USN-4978-1] Firefox vulnerabilities [03:40]
“Total Cookie Protection” - confines cookies to the site where they
were created to avoid tracking across sites - PLUS a bunch of security
fixes including
mode - would then surface this next time you choose to print a file
[USN-4980-1] polkit vulnerability [04:43]
permitted to perform an action - to do this, they send the DBus name of
the process to polkit and it looks up the resulting uid/pid via an
internal function polkit_system_bus_name_get_creds_sync() - logic error
within policykit when looking if the process in question were to
disconnect from DBus at the right time, policykit would return an error
but also a boolean TRUE value indicating success (depends on how the
daemon interpreted this value with an associated error). This could then
allow an application which was not privileged to be able to perform more
privileged actions. Fixed to actually return FALSE in this case and avoid
any potential confusion.
[USN-4981-1] Squid vulnerabilities [06:11]
remote attackers
[USN-4969-3] DHCP regression [06:28]
config files would be seen as invalid and rejected and hence
isc-dhcp-server would fail to start - actually caused as a result of the
newer toolchain used in 21.04 - has stricter aliasing checking and so
would treat certain operations introduced in this change as UB and change
code-flow as a result. Fixed by disabling this stricter aliasing checking
in the build to restore the original behaviour.
[USN-4937-2] GNOME Autoar regression [07:22]
directory would be created if an archive contained a file of the same
name as the archive itself - fixed to avoid creating this directory first
so that files would then actually get created as expected
[USN-4985-1] Intel Microcode vulnerabilities [07:48]
issues for particular processors PLUS potential stability issues that
have been seen in previous microcode releases (processor would hang if
tried to load a too new microcode version compared to the one contained
within the BIOS)
an issue which would result in EIBRS (Spectre) mitigations not being
applied, cache-lines not being flushed properly and a speculative
execution issue specific to Atom processors via micro-arch buffers.
[USN-4986-1] rpcbind vulnerability [09:02]
requests - could then be made to crash by allocating too much memory
Goings on in Ubuntu Security Community
odrive-unofficial snap investigation [09:20]
The magic behind snap interfaces [12:36]
Get in contact
View all episodes
By Ubuntu Security Team
4.8
1010 ratings
Overview
This week we cover security updates for the Linux kernel, PolicyKit, Intel
Microcode and more, plus we look at a report of an apparent malicious snap
in the Snap Store and some of the mechanics behind snap confinement.
This week in Ubuntu Security Updates
42 unique CVEs addressed
[USN-4979-1] Linux kernel vulnerabilities [01:04]
mounting an malicious ext4 image -> crash (DoS)
[USN-4982-1] Linux kernel vulnerabilities [02:23]
[USN-4984-1] Linux kernel vulnerabilities [02:39]
[USN-4977-1] Linux kernel vulnerabilities
connection between two NFC devices
[USN-4983-1] Linux kernel (OEM) vulnerabilities [03:32]
programs which could cause speculative loads -> info leak
[USN-4978-1] Firefox vulnerabilities [03:40]
“Total Cookie Protection” - confines cookies to the site where they
were created to avoid tracking across sites - PLUS a bunch of security
fixes including
mode - would then surface this next time you choose to print a file
[USN-4980-1] polkit vulnerability [04:43]
permitted to perform an action - to do this, they send the DBus name of
the process to polkit and it looks up the resulting uid/pid via an
internal function polkit_system_bus_name_get_creds_sync() - logic error
within policykit when looking if the process in question were to
disconnect from DBus at the right time, policykit would return an error
but also a boolean TRUE value indicating success (depends on how the
daemon interpreted this value with an associated error). This could then
allow an application which was not privileged to be able to perform more
privileged actions. Fixed to actually return FALSE in this case and avoid
any potential confusion.
[USN-4981-1] Squid vulnerabilities [06:11]
remote attackers
[USN-4969-3] DHCP regression [06:28]
config files would be seen as invalid and rejected and hence
isc-dhcp-server would fail to start - actually caused as a result of the
newer toolchain used in 21.04 - has stricter aliasing checking and so
would treat certain operations introduced in this change as UB and change
code-flow as a result. Fixed by disabling this stricter aliasing checking
in the build to restore the original behaviour.
[USN-4937-2] GNOME Autoar regression [07:22]
directory would be created if an archive contained a file of the same
name as the archive itself - fixed to avoid creating this directory first
so that files would then actually get created as expected
[USN-4985-1] Intel Microcode vulnerabilities [07:48]
issues for particular processors PLUS potential stability issues that
have been seen in previous microcode releases (processor would hang if
tried to load a too new microcode version compared to the one contained
within the BIOS)
an issue which would result in EIBRS (Spectre) mitigations not being
applied, cache-lines not being flushed properly and a speculative
execution issue specific to Atom processors via micro-arch buffers.
[USN-4986-1] rpcbind vulnerability [09:02]
requests - could then be made to crash by allocating too much memory
Goings on in Ubuntu Security Community
odrive-unofficial snap investigation [09:20]
The magic behind snap interfaces [12:36]
Get in contact