CVE-2022-37966

Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability

Samba is a suite of programs for Linux and Unix to interoperate with Windows.

Security Fix(es):

Since the Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability was disclosed by Microsoft on Nov 8 2022 and per RFC8429 it is assumed that rc4-hmac is weak, Vulnerable Samba Active Directory DCs will issue rc4-hmac encrypted tickets despite the target server supporting better encryption (eg aes256-cts-hmac-sha1-96).(CVE-2022-45141)

Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability.(CVE-2022-37966)

Samba is a suite of programs for Linux and Unix to interoperate with Windows.

Security Fix(es):

Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability.(CVE-2022-37966)

Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability

Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability

• SECURITY UPDATE: Kerberos KDC elevation of privilege via weak RC4 session keys
  • debian/patches/CVE-2022-37966.patch: prefer AES over RC4 for Kerberos session keys by selecting the session key from the server's advertised session etypes, strip weak keys from the krbtgt account, leave UF_USE_DES_KEY_ONLY accounts without usable keys as upstream does, declare RC4 support explicitly on trust objects created by samba-tool (upstream 84c28b05a0a), and add "kdc default domain supported enctypes", "kdc supported enctypes" and "kdc force enable rc4 weak session keys" options
  • debian/patches/CVE-2022-37966.patch: free the newly added sdb_entry etypes/session_etypes members, the calloc'ed etypes->val array, and the krbtgt keys discarded when the key list is truncated to one (upstream 75a1beeea85, a97aad91878, 149d4364299), avoiding a per-request KDC memory leak
  • debian/patches/CVE-2022-37966-domain-trust-modify.patch: add the upstream "samba-tool domain trust modify" command (upstream d1999c15, same CVE-2022-37966 series) so an administrator has a supported CLI to repair a pre-existing RC4-only trust after the change above stopped assuming RC4 support on trust objects
  • CVE-2022-37966

There is a limited write heap buffer overflow in the GSSAPI unwrap_des() and unwrap_des3() routines of Heimdal (included in Samba). Some SMB1 write requests were not correctly range checked to ensure the client had sent enough data to fulfill the write, allowing server memory contents to be written into the file (or printer) instead of client supplied data. The client cannot control the area of the server memory that is written to the file (or printer) (CVE-2022-3437)

A symlink following vulnerability was found in Samba, where a user can create a symbolic link that will make 'smbd' escape the configured share path. This flaw allows a remote user with access to the exported part of the file system under a share via SMB1 unix extensions or NFS to create symlinks to files outside the 'smbd' configured share path and gain access to another restricted server's filesystem. (CVE-2022-3592)

Active directory elevation of privilege vulnerability (CVE-2022-37966)

Active directory elevation of privilege vulnerability (CVE-2022-37967)

A flaw was found in samba. The Netlogon RPC implementations may use the rc4-hmac encryption algorithm, which is considered weak and should be avoided even if the client supports more modern encryption types. This issue could allow an attacker who knows the plain text content communicated between the samba client and server to craft data with the same MD5 calculation and replace it without being detected. (CVE-2022-38023)

Active directory integer overflow (CVE-2022-42898)

Active directory can be forced to issue weak rc4-hmac encrypted tickets (CVE-2022-45141)

These are all security issues fixed in the ctdb-4.17.4+git.300.305b22bfce-1.1 package on the GA media of openSUSE Tumbleweed.

This update for samba fixes the following issues:

Update to 4.15.13

• CVE-2022-37966 rc4-hmac Kerberos session keys issued to modern servers (bsc#1205385).
• CVE-2022-37967 Kerberos constrained delegation ticket forgery possible against Samba AD DC (bsc#1205386).
• CVE-2022-38023 RC4/HMAC-MD5 NetLogon Secure Channel is weak and should be avoided (bsc#1206504).
• Fixed issue with bind start up (bsc#1205946).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed an issue where the bad password count would not be properly incremented, which could allow attackers to brute force a user's password (bsc#1206546).
• CVE-2022-38023: Disabled weak ciphers by default in the Netlogon Secure channel (bsc#1206504).
• CVE-2022-37966: Fixed an issue where a weak cipher would be selected to encrypt session keys, which could lead to privilege escalation (bsc#1205385).
• CVE-2020-14323: Fixed a denial of service in winbindd (bsc#1173994).
• CVE-2022-32742: Fixed incorrect length check in SMB1write, SMB1write_and_close, SMB1write_and_unlock (bsc#1201496).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed an issue where the bad password count would not be properly incremented, which could allow attackers to brute force a user's password (bsc#1206546).
• CVE-2022-38023: Disabled weak ciphers by default in the Netlogon Secure channel (bsc#1206504).
• CVE-2022-37966: Fixed an issue where a weak cipher would be selected to encrypt session keys, which could lead to privilege escalation (bsc#1205385).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed an issue where the bad password count would not be properly incremented, which could allow attackers to brute force a user's password (bsc#1206546).

• Updated to version 4.15.13:

  • CVE-2022-37966: Fixed an issue where a weak cipher would be selected to encrypt session keys, which could lead to privilege escalation (bsc#1205385).
  • CVE-2022-37967: Fixed a potential privilege escalation issue via constrained delegation due to weak a cryptographic algorithm being selected (bsc#1205386).
  • CVE-2022-38023: Disabled weak ciphers by default in the Netlogon Secure channel (bsc#1206504).

• Updated to version 4.15.12:

  • CVE-2022-42898: Fixed several buffer overflow vulnerabilities on 32-bit systems (bsc#1205126).

• Updated to version 4.15.11:

  • CVE-2022-3437: Fixed a buffer overflow in Heimdal unwrap_des3() (bsc#1204254).

• Updated to version 4.15.10:

  • Fixed a potential crash due to a concurrency issue (bsc#1200102).

• Updated to version 4.15.9:

  • CVE-2022-32742: Fixed an information leak that could be triggered via SMB1 (bsc#1201496).
  • CVE-2022-32746: Fixed a memory corruption issue in database audit logging (bsc#1201490).
  • CVE-2022-2031: Fixed AD restrictions bypass associated with changing passwords (bsc#1201495).
  • CVE-2022-32745: Fixed a remote server crash that could be triggered with certain LDAP requests (bsc#1201492).
  • CVE-2022-32744: Fixed an issue where AD users could have forged password change requests on behalf of other users (bsc#1201493).

Other fixes:

• Fixed a problem when using bind as samba-ad-dc backend related to the named service (bsc#1201689).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed an issue where the bad password count would not be properly incremented, which could allow attackers to brute force a user's password (bsc#1206546).
• CVE-2022-38023: Disabled weak ciphers by default in the Netlogon Secure channel (bsc#1206504).
• CVE-2022-37966: Fixed an issue where a weak cipher would be selected to encrypt session keys, which could lead to privilege escalation (bsc#1205385).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed an issue where the bad password count would not be properly incremented, which could allow attackers to brute force a user's password (bsc#1206546).
• CVE-2022-37966: Fixed an issue where a weak cipher would be selected to encrypt session keys, which could lead to privilege escalation (bsc#1205385).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed an issue where the bad password count would not be properly incremented, which could allow attackers to brute force a user's password (bsc#1206546).
• CVE-2022-38023: Disabled weak ciphers by default in the Netlogon Secure channel (bsc#1206504).
• CVE-2022-37966: Fixed an issue where a weak cipher would be selected to encrypt session keys, which could lead to privilege escalation (bsc#1205385).

This update for samba fixes the following issues:

• CVE-2021-20251: Fixed bad password count that was not incremented atomically (bsc#1206546).
• CVE-2022-38023: Fixed weak RC4/HMAC-MD5 NetLogon Secure Channel usage should be avoided (bsc#1206504).
• CVE-2022-37966: Fixed privilege elevation vulnerability with option 'kerberos encryption types = legacy' which would force RC4-HMAC as a client even if the server supports AES (bsc#1205385).

It was discovered that Samba incorrectly handled the bad password count logic. A remote attacker could possibly use this issue to bypass bad passwords lockouts. This issue was only addressed in Ubuntu 22.10. (CVE-2021-20251)

Evgeny Legerov discovered that Samba incorrectly handled buffers in certain GSSAPI routines of Heimdal. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2022-3437)

Tom Tervoort discovered that Samba incorrectly used weak rc4-hmac Kerberos keys. A remote attacker could possibly use this issue to elevate privileges. (CVE-2022-37966, CVE-2022-37967)

It was discovered that Samba supported weak RC4/HMAC-MD5 in NetLogon Secure Channel. A remote attacker could possibly use this issue to elevate privileges. (CVE-2022-38023)

Greg Hudson discovered that Samba incorrectly handled PAC parsing. On 32-bit systems, a remote attacker could use this issue to escalate privileges, or possibly execute arbitrary code. (CVE-2022-42898)

Joseph Sutton discovered that Samba could be forced to issue rc4-hmac encrypted Kerberos tickets. A remote attacker could possibly use this issue to escalate privileges. This issue only affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2022-45141)

WARNING: The fixes included in these updates introduce several important behavior changes which may cause compatibility problems interacting with systems still expecting the former behavior. Please see the following upstream advisories for more information:

https://www.samba.org/samba/security/CVE-2022-37966.html https://www.samba.org/samba/security/CVE-2022-37967.html https://www.samba.org/samba/security/CVE-2022-38023.html

Evgeny Legerov discovered that Samba incorrectly handled buffers in certain GSSAPI routines of Heimdal. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2022-3437)

Tom Tervoort discovered that Samba incorrectly used weak rc4-hmac Kerberos keys. A remote attacker could possibly use this issue to elevate privileges. (CVE-2022-37966, CVE-2022-37967)

It was discovered that Samba supported weak RC4/HMAC-MD5 in NetLogon Secure Channel. A remote attacker could possibly use this issue to elevate privileges. (CVE-2022-38023)

Greg Hudson discovered that Samba incorrectly handled PAC parsing. On 32-bit systems, a remote attacker could use this issue to escalate privileges, or possibly execute arbitrary code. (CVE-2022-42898)

Joseph Sutton discovered that Samba could be forced to issue rc4-hmac encrypted Kerberos tickets. A remote attacker could possibly use this issue to escalate privileges. This issue only affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2022-45141)

WARNING: This update upgrades the version of Samba to 4.15.13. Please see the upstream release notes for important changes in the new version:

https://www.samba.org/samba/history/samba-4.15.0.html

In addition, the security fixes included in this new version introduce several important behavior changes which may cause compatibility problems interacting with systems still expecting the former behavior. Please see the following upstream advisories for more information:

https://www.samba.org/samba/security/CVE-2022-37966.html https://www.samba.org/samba/security/CVE-2022-37967.html https://www.samba.org/samba/security/CVE-2022-38023.html