Vulnerabilities (CVE)

A flaw was found in samba. A race condition in the password lockout code may lead to the risk of brute force attacks being successful if special conditions are met.

A flaw was found in samba. Spaces used in a string around a domain name (DN), while supposed to be ignored, can cause invalid DN strings with spaces to instead write a zero-byte into out-of-bounds memory, resulting in a crash. The highest threat from this vulnerability is to system availability.

Multiple flaws were found in the way samba AD DC implemented access and conformance checking of stored data. An attacker could use this flaw to cause total domain compromise.

Kerberos acceptors need easy access to stable AD identifiers (eg objectSid). Samba as an AD DC now provides a way for Linux applications to obtain a reliable SID (and samAccountName) in issued tickets.

A flaw was found in the way Samba, as an Active Directory Domain Controller, implemented Kerberos name-based authentication. The Samba AD DC, could become confused about the user a ticket represents if it did not strictly require a Kerberos PAC and always use the SIDs found within. The result could include total domain compromise.

A flaw was found in the way samba, as an Active Directory Domain Controller, is able to support an RODC (read-only domain controller). This would allow an RODC to print administrator tickets.

A flaw was found in the way Samba maps domain users to local users. An authenticated attacker could use this flaw to cause possible privilege escalation.

A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used for delegation via Kerberos Constrained Delegation (KCD). To exploit the vulnerability, a compromised service that is configured to use KCD could tamper with a service ticket that is not valid for delegation to force the KDC to accept it. The update addresses this vulnerability by changing how the KDC validates service tickets used with KCD.

A flaw was found in samba's DNS server. An authenticated user could use this flaw to the RPC server to crash. This RPC server, which also serves protocols other than dnsserver, will be restarted after a short delay, but it is easy for an authenticated non administrative attacker to crash it again as soon as it returns. The Samba DNS server itself will continue to operate, but many RPC services will not.

A null pointer dereference flaw was found in samba's Winbind service in versions before 4.11.15, before 4.12.9 and before 4.13.1. A local user could use this flaw to crash the winbind service causing denial of service.

A flaw was found in the way samba handled file and directory permissions. An authenticated user could use this flaw to gain access to certain file and directory information which otherwise would be unavailable to the attacker.

A flaw was found in the AD DC NBT server in all Samba versions before 4.10.17, before 4.11.11 and before 4.12.4. A samba user could send an empty UDP packet to cause the samba server to crash.

A use-after-free flaw was found in all samba LDAP server versions before 4.10.17, before 4.11.11, before 4.12.4 used in a AC DC configuration. A Samba LDAP user could use this flaw to crash samba.

A flaw was found in all Samba versions before 4.10.17, before 4.11.11 and before 4.12.4 in the way it processed NetBios over TCP/IP. This flaw allows a remote attacker could to cause the Samba server to consume excessive CPU use, resulting in a denial of service. This highest threat from this vulnerability is to system availability.

A NULL pointer dereference, or possible use-after-free flaw was found in Samba AD LDAP server in versions before 4.10.17, before 4.11.11 and before 4.12.4. Although some versions of Samba shipped with Red Hat Enterprise Linux do not support Samba in AD mode, the affected code is shipped with the libldb package. This flaw allows an authenticated user to possibly trigger a use-after-free or NULL pointer dereference. The highest threat from this vulnerability is to system availability.

A flaw was found when using samba as an Active Directory Domain Controller. Due to the way samba handles certain requests as an Active Directory Domain Controller LDAP server, an unauthorized user can cause a stack overflow leading to a denial of service. The highest threat from this vulnerability is to system availability. This issue affects all samba versions before 4.10.15, before 4.11.8 and before 4.12.2.

A use-after-free flaw was found in the way samba AD DC LDAP servers, handled 'Paged Results' control is combined with the 'ASQ' control. A malicious user in a samba AD could use this flaw to cause denial of service. This issue affects all samba versions before 4.10.15, before 4.11.8 and before 4.12.2.

A flaw was found in the way samba implemented an RPC endpoint emulating the Windows registry service API. An unprivileged attacker could use this flaw to create a new registry hive file anywhere they have unix permissions which could lead to creation of a new file in the Samba share. Versions before 4.8.11, 4.9.6 and 4.10.2 are vulnerable.

A flaw was found in the way an LDAP search expression could crash the shared LDAP server process of a samba AD DC in samba before version 4.10. An authenticated user, having read permissions on the LDAP server, could use this flaw to cause denial of service.

There is an issue in all samba 4.11.x versions before 4.11.5, all samba 4.10.x versions before 4.10.12 and all samba 4.9.x versions before 4.9.18, where the removal of the right to create or modify a subtree would not automatically be taken away on all domain controllers.

All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the S4U (MS-SFU) Kerberos delegation model includes a feature allowing for a subset of clients to be opted out of constrained delegation in any way, either S4U2Self or regular Kerberos authentication, by forcing all tickets for these clients to be non-forwardable. In AD this is implemented by a user attribute delegation_not_allowed (aka not-delegated), which translates to disallow-forwarda ... All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the S4U (MS-SFU) Kerberos delegation model includes a feature allowing for a subset of clients to be opted out of constrained delegation in any way, either S4U2Self or regular Kerberos authentication, by forcing all tickets for these clients to be non-forwardable. In AD this is implemented by a user attribute delegation_not_allowed (aka not-delegated), which translates to disallow-forwardable. However the Samba AD DC does not do that for S4U2Self and does set the forwardable flag even if the impersonated client has the not-delegated flag set.

Show More

All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the (poorly named) dnsserver RPC pipe provides administrative facilities to modify DNS records and zones. Samba, when acting as an AD DC, stores DNS records in LDAP. In AD, the default permissions on the DNS partition allow creation of new records by authenticated users. This is used for example to allow machines to self-register in DNS. If a DNS record was created that case-insensitively ... All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the (poorly named) dnsserver RPC pipe provides administrative facilities to modify DNS records and zones. Samba, when acting as an AD DC, stores DNS records in LDAP. In AD, the default permissions on the DNS partition allow creation of new records by authenticated users. This is used for example to allow machines to self-register in DNS. If a DNS record was created that case-insensitively matched the name of the zone, the ldb_qsort() and dns_name_compare() routines could be confused into reading memory prior to the list of DNS entries when responding to DnssrvEnumRecords() or DnssrvEnumRecords2() and so following invalid memory as a pointer.

Show More

A flaw was found in samba 4.0.0 before samba 4.9.15 and samba 4.10.x before 4.10.10. An attacker can crash AD DC LDAP server via dirsync resulting in denial of service. Privilege escalation is not possible with this issue.

A flaw was found in Samba, all versions starting samba 4.5.0 before samba 4.9.15, samba 4.10.10, samba 4.11.2, in the way it handles a user password change or a new password for a samba user. The Samba Active Directory Domain Controller can be configured to use a custom script to check for password complexity. This configuration can fail to verify password complexity when non-ASCII characters are used in the password, which could lead to weak passwords being set for samba users, making it vulner ... A flaw was found in Samba, all versions starting samba 4.5.0 before samba 4.9.15, samba 4.10.10, samba 4.11.2, in the way it handles a user password change or a new password for a samba user. The Samba Active Directory Domain Controller can be configured to use a custom script to check for password complexity. This configuration can fail to verify password complexity when non-ASCII characters are used in the password, which could lead to weak passwords being set for samba users, making it vulnerable to dictionary attacks.

Show More

Samba 4.10.x before 4.10.5 has a NULL pointer dereference, leading to an AD DC LDAP server Denial of Service. This is related to an attacker using the paged search control. The attacker must have directory read access in order to attempt an exploit.

Samba 4.9.x before 4.9.9 and 4.10.x before 4.10.5 has a NULL pointer dereference, leading to Denial of Service. This is related to the AD DC DNS management server (dnsserver) RPC server process.

A flaw was found in the samba client, all samba versions before samba 4.11.2, 4.10.10 and 4.9.15, where a malicious server can supply a pathname to the client with separators. This could allow the client to access files and folders outside of the SMB network pathnames. An attacker could use this vulnerability to create files outside of the current working directory using the privileges of the client user.

A flaw was found in samba versions 4.9.x up to 4.9.13, samba 4.10.x up to 4.10.8 and samba 4.11.x up to 4.11.0rc3, when certain parameters were set in the samba configuration file. An unauthenticated attacker could use this flaw to escape the shared directory and access the contents of directories outside the share.

A missing input sanitization flaw was found in the implementation of LDP database used for the LDAP server. An attacker could use this flaw to cause a denial of service against a samba server, used as a Active Directory Domain Controller. All versions of Samba from 4.8.0 onwards are vulnerable

A flaw was found in the way samba before 4.7.9 and 4.8.4 allowed the use of weak NTLMv1 authentication even when NTLMv1 was explicitly disabled. A man-in-the-middle attacker could use this flaw to read the credential and other details passed between the samba server and client.

On a Samba 4 AD DC the LDAP server in all versions of Samba from 4.0.0 onwards incorrectly validates permissions to modify passwords over LDAP allowing authenticated users to change any other users' passwords, including administrative users and privileged service accounts (eg Domain Controllers).

All versions of Samba from 4.0.0 onwards are vulnerable to a denial of service attack when the RPC spoolss service is configured to be run as an external daemon. Missing input sanitization checks on some of the input parameters to spoolss RPC calls could cause the print spooler service to crash.

A flaw was found in samba's Heimdal KDC implementation, versions 4.8.x up to, excluding 4.8.12, 4.9.x up to, excluding 4.9.8 and 4.10.x up to, excluding 4.10.3, when used in AD DC mode. A man in the middle attacker could use this flaw to intercept the request to the KDC and replace the user name (principal) in the request with any desired user name (principal) that exists in the KDC effectively obtaining a ticket for that principal.

Samba from version 4.9.0 and before version 4.9.3 that have AD DC configurations watching for bad passwords (to restrict brute forcing of passwords) in a window of more than 3 minutes may not watch for bad passwords at all. The primary risk from this issue is with regards to domains that have been upgraded from Samba 4.8 and earlier. In these cases the manual testing done to confirm an organisation's password policies apply as expected may not have been re-done after the upgrade.

Samba from version 4.7.0 has a vulnerability that allows a user in a Samba AD domain to crash the KDC when Samba is built in the non-default MIT Kerberos configuration. With this advisory the Samba Team clarify that the MIT Kerberos build of the Samba AD DC is considered experimental. Therefore the Samba Team will not issue security patches for this configuration. Additionally, Samba 4.7.12, 4.8.7 and 4.9.3 have been issued as security releases to prevent building of the AD DC with MIT Kerberos ... Samba from version 4.7.0 has a vulnerability that allows a user in a Samba AD domain to crash the KDC when Samba is built in the non-default MIT Kerberos configuration. With this advisory the Samba Team clarify that the MIT Kerberos build of the Samba AD DC is considered experimental. Therefore the Samba Team will not issue security patches for this configuration. Additionally, Samba 4.7.12, 4.8.7 and 4.9.3 have been issued as security releases to prevent building of the AD DC with MIT Kerberos unless --with-experimental-mit-ad-dc is specified to the configure command.

Show More

Samba from version 4.9.0 and before version 4.9.3 is vulnerable to a NULL pointer de-reference. During the processing of an DNS zone in the DNS management DCE/RPC server, the internal DNS server or the Samba DLZ plugin for BIND9, if the DSPROPERTY_ZONE_MASTER_SERVERS property or DSPROPERTY_ZONE_SCAVENGING_SERVERS property is set, the server will follow a NULL pointer and terminate. There is no further vulnerability associated with this issue, merely a denial of service.

Samba from version 4.0.0 and before versions 4.7.12, 4.8.7, 4.9.3 is vulnerable to a denial of service. During the processing of an LDAP search before Samba's AD DC returns the LDAP entries to the client, the entries are cached in a single memory object with a maximum size of 256MB. When this size is reached, the Samba process providing the LDAP service will follow the NULL pointer, terminating the process. There is no further vulnerability associated with this issue, merely a denial of service.

Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), term ... Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), terminating the KDC process.

Show More

A denial of service vulnerability was discovered in Samba's LDAP server before versions 4.7.12, 4.8.7, and 4.9.3. A CNAME loop could lead to infinite recursion in the server. An unprivileged local attacker could create such an entry, leading to denial of service.

The Samba Active Directory LDAP server was vulnerable to an information disclosure flaw because of missing access control checks. An authenticated attacker could use this flaw to extract confidential attribute values using LDAP search expressions. Samba versions before 4.6.16, 4.7.9 and 4.8.4 are vulnerable.