Ubuntu Security Notice USN-4171-6
November 12, 2020
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 20.10
– Ubuntu 20.04 LTS
– Ubuntu 18.04 LTS
– Ubuntu 16.04 LTS
USN-4171-1 introduced a regression in Apport.
– apport: automatically generate crash reports for debugging
USN-4171-1 fixed vulnerabilities in Apport. The update caused a regression
when handling configuration files. This update fixes the problem, and also
introduces further hardening measures.
Original advisory details:
Kevin Backhouse discovered Apport would read its user-controlled settings
file as the root user. This could be used by a local attacker to possibly
crash Apport or have other unspecified consequences. (CVE-2019-11481)
Sander Bos discovered a race-condition in Apport during core dump
creation. This could be used by a local attacker to generate a crash report
for a privileged process that is readable by an unprivileged user.
Sander Bos discovered Apport mishandled crash dumps originating from
containers. This could be used by a local attacker to generate a crash
report for a privileged process that is readable by an unprivileged user.
Sander Bos discovered Apport mishandled lock-file creation. This could be
used by a local attacker to cause a denial of service against Apport.
Kevin Backhouse discovered Apport read various process-specific files with
elevated privileges during crash dump generation. This could could be used
by a local attacker to generate a crash report for a privileged process
that is readable by an unprivileged user. (CVE-2019-15790)
The problem can be corrected by updating your system to the following
Ubuntu 20.04 LTS:
Ubuntu 18.04 LTS:
Ubuntu 16.04 LTS:
In general, a standard system update will make all the necessary changes.