USN-5142-2: Samba regressions
6 December 2021
USN-5142-1 introduced regressions in Samba.
Releases
Packages
- samba - SMB/CIFS file, print, and login server for Unix
Details
USN-5142-1 fixed vulnerabilities in Samba. Some of the upstream changes
introduced regressions in name mapping and backups.
Please see the following upstream bugs for more information:
https://bugzilla.samba.org/show_bug.cgi?id=14901
https://bugzilla.samba.org/show_bug.cgi?id=14918
This update fixes the problem.
Original advisory details:
Stefan Metzmacher discovered that Samba incorrectly handled SMB1 client
connections. A remote attacker could possibly use this issue to downgrade
connections to plaintext authentication. (CVE-2016-2124)
Andrew Bartlett discovered that Samba incorrectly mapping domain users to
local users. An authenticated attacker could possibly use this issue to
become root on domain members. (CVE-2020-25717)
Andrew Bartlett discovered that Samba did not correctly sandbox Kerberos
tickets issues by an RODC. An RODC could print administrator tickets,
contrary to expectations. (CVE-2020-25718)
Andrew Bartlett discovered that Samba incorrectly handled Kerberos tickets.
Delegated administrators could possibly use this issue to impersonate
accounts, leading to total domain compromise. (CVE-2020-25719)
Andrew Bartlett discovered that Samba did not provide stable AD
identifiers to Kerberos acceptors. (CVE-2020-25721)
Andrew Bartlett discovered that Samba did not properly check sensitive
attributes. An authenticated attacker could possibly use this issue to
escalate privileges. (CVE-2020-25722)
Stefan Metzmacher discovered that Samba incorrectly handled certain large
DCE/RPC requests. A remote attacker could possibly use this issue to
bypass signature requirements. (CVE-2021-23192)
William Ross discovered that Samba incorrectly handled memory. A remote
attacker could use this issue to cause Samba to crash, resulting in a
denial of service, or possibly escalate privileges. (CVE-2021-3738)
Joseph Sutton discovered that Samba incorrectly handled certain TGS
requests. An authenticated attacker could possibly use this issue to cause
Samba to crash, resulting in a denial of service. (CVE-2021-3671)
The fix for CVE-2020-25717 results in possible behaviour changes that could
affect certain environments. Please see the upstream advisory for more
information:
Update instructions
The problem can be corrected by updating your system to the following package versions:
Ubuntu 21.10
Ubuntu 21.04
Ubuntu 20.04
In general, a standard system update will make all the necessary changes.