A Samba security update has been released for Ubuntu Linux 20.04 LTS, 22.04 LTS, and 23.04.

[USN-6425-1] Samba vulnerabilities

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Ubuntu Security Notice USN-6425-1
October 10, 2023

samba vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 23.04
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS

Summary:

Several security issues were fixed in Samba.

Software Description:
- samba: SMB/CIFS file, print, and login server for Unix

Details:

Sri Nagasubramanian discovered that the Samba acl_xattr VFS module
incorrectly handled read-only files. When Samba is configured to ignore
system ACLs, a remote attacker could possibly use this issue to truncate
read-only files. (CVE-2023-4091)

Andrew Bartlett discovered that Samba incorrectly handled the DirSync
control. A remote attacker with an RODC DC account could possibly use this
issue to obtain all domain secrets. (CVE-2023-4154)

Andrew Bartlett discovered that Samba incorrectly handled the rpcecho
development server. A remote attacker could possibly use this issue to
cause Samba to stop responding, resulting in a denial of service.
(CVE-2023-42669)

Kirin van der Veer discovered that Samba incorrectly handled certain RPC
service listeners. A remote attacker could possibly use this issue to cause
Samba to start multiple incompatible RPC listeners, resulting in a denial
of service. This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04.
(CVE-2023-42670)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 23.04:
samba 2:4.17.7+dfsg-1ubuntu2.3

Ubuntu 22.04 LTS:
samba 2:4.15.13+dfsg-0ubuntu1.5

Ubuntu 20.04 LTS:
samba 2:4.15.13+dfsg-0ubuntu0.20.04.6

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-6425-1
CVE-2023-4091, CVE-2023-4154, CVE-2023-42669, CVE-2023-42670

Package Information:
https://launchpad.net/ubuntu/+source/samba/2:4.17.7+dfsg-1ubuntu2.3
https://launchpad.net/ubuntu/+source/samba/2:4.15.13+dfsg-0ubuntu1.5
https://launchpad.net/ubuntu/+source/samba/2:4.15.13+dfsg-0ubuntu0.20.04.6