USN-5142-1: Samba vulnerabilities

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: https://www.samba.org/samba/security/CVE-2020-25717.html