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AUSCERT External Security Bulletin Redistribution
USN-5067-1: SSSD vulnerabilities
9 September 2021
AusCERT Security Bulletin Summary
Operating System: Ubuntu
Impact/Access: Root Compromise -- Existing Account
Execute Arbitrary Code/Commands -- Existing Account
Access Confidential Data -- Existing Account
CVE Names: CVE-2021-3621 CVE-2019-3811 CVE-2018-16838
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USN-5067-1: SSSD vulnerabilities
08 September 2021
Several security issues were fixed in sssd.
o Ubuntu 21.04
o Ubuntu 20.04 LTS
o Ubuntu 18.04 LTS
o sssd - System Security Services Daemon
Jakub Hrozek discovered that SSSD incorrectly handled file permissions. A
local attacker could possibly use this issue to read the sudo rules
available for any user. This issue only affected Ubuntu 18.04 LTS.
( CVE-2018-10852 )
It was discovered that SSSD incorrectly handled Group Policy Objects. When
SSSD is configured with too strict permissions causing the GPO to not be
readable, SSSD will allow all authenticated users to login instead of being
denied, contrary to expectations. This issue only affected Ubuntu 18.04
LTS. ( CVE-2018-16838 )
It was discovered that SSSD incorrectly handled users with no home
directory set. When no home directory was set, SSSD would return the root
directory instead of an empty string, possibly bypassing security measures.
This issue only affected Ubuntu 18.04 LTS. ( CVE-2019-3811 )
Cedric Buissart discovered that SSSD incorrectly handled the sssctl
command. In certain environments, a local user could use this issue to
execute arbitrary commands and possibly escalate privileges.
( CVE-2021-3621 )
The problem can be corrected by updating your system to the following package
o sssd - 2.4.0-1ubuntu6.1
o sssd - 2.2.3-3ubuntu0.7
o sssd - 1.16.1-1ubuntu1.8
In general, a standard system update will make all the necessary changes.
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