==========================================================================
Ubuntu Security Notice USN-5828-1
January 25, 2023

krb5 vulnerabilities
==========================================================================

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

- Ubuntu 22.10
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in Kerberos.

Software Description:
- krb5: MIT Kerberos Network Authentication Protocol

Details:

It was discovered that Kerberos incorrectly handled certain S4U2Self
requests. An attacker could possibly use this issue to cause a denial of
service. This issue was only addressed in Ubuntu 16.04 ESM and Ubuntu
18.04 LTS. (CVE-2018-20217)

Greg Hudson discovered that Kerberos PAC implementation incorrectly
handled certain parsing operations. A remote attacker could use this
issue to cause a denial of service, or possibly execute arbitrary code.
(CVE-2022-42898)

Update instructions:

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

Ubuntu 22.10:
   krb5-admin-server               1.20-1ubuntu0.1
   krb5-kdc                        1.20-1ubuntu0.1
   krb5-user                       1.20-1ubuntu0.1
   libgssapi-krb5-2                1.20-1ubuntu0.1
   libkdb5-10                      1.20-1ubuntu0.1

Ubuntu 22.04 LTS:
   krb5-admin-server               1.19.2-2ubuntu0.1
   krb5-kdc                        1.19.2-2ubuntu0.1
   krb5-user                       1.19.2-2ubuntu0.1
   libgssapi-krb5-2                1.19.2-2ubuntu0.1
   libkdb5-10                      1.19.2-2ubuntu0.1

Ubuntu 20.04 LTS:
   krb5-admin-server               1.17-6ubuntu4.2
   krb5-kdc                        1.17-6ubuntu4.2
   krb5-user                       1.17-6ubuntu4.2
   libgssapi-krb5-2                1.17-6ubuntu4.2
   libkdb5-9                       1.17-6ubuntu4.2

Ubuntu 18.04 LTS:
   krb5-admin-server               1.16-2ubuntu0.3
   krb5-kdc                        1.16-2ubuntu0.3
   krb5-user                       1.16-2ubuntu0.3
   libgssapi-krb5-2                1.16-2ubuntu0.3
   libkdb5-9                       1.16-2ubuntu0.3

Ubuntu 16.04 ESM:
   krb5-admin-server               1.13.2+dfsg-5ubuntu2.2+esm3
   krb5-kdc                        1.13.2+dfsg-5ubuntu2.2+esm3
   krb5-user                       1.13.2+dfsg-5ubuntu2.2+esm3
   libgssapi-krb5-2                1.13.2+dfsg-5ubuntu2.2+esm3
   libkdb5-8                       1.13.2+dfsg-5ubuntu2.2+esm3

Ubuntu 14.04 ESM:
   krb5-admin-server               1.12+dfsg-2ubuntu5.4+esm3
   krb5-kdc                        1.12+dfsg-2ubuntu5.4+esm3
   krb5-user                       1.12+dfsg-2ubuntu5.4+esm3
   libgssapi-krb5-2                1.12+dfsg-2ubuntu5.4+esm3
   libkdb5-7                       1.12+dfsg-2ubuntu5.4+esm3

After a standard system update you need to restart any application
using Kerberos libraries to make all the necessary changes.

References:
   https://ubuntu.com/security/notices/USN-5828-1
   CVE-2018-20217, CVE-2022-42898

Package Information:
   https://launchpad.net/ubuntu/+source/krb5/1.20-1ubuntu0.1
   https://launchpad.net/ubuntu/+source/krb5/1.19.2-2ubuntu0.1
   https://launchpad.net/ubuntu/+source/krb5/1.17-6ubuntu4.2
   https://launchpad.net/ubuntu/+source/krb5/1.16-2ubuntu0.3