In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections via a mechanism called 'association groups'. These handles can reference connections to our sam.ldb database. However while the database was correctly shared, the user credentials state was only pointed at, and when one connection within that association group ended, the database would be left pointing at an invalid 'struct session_info'. The most likely outcome here is a crash, but it is possible that the use-after-free could instead allow different user state to be pointed at and this might allow more privileged access.
The Samba vfs_fruit module uses extended file attributes (EA, xattr) to provide "...enhanced compatibility with Apple SMB clients and interoperability with a Netatalk 3 AFP fileserver." Samba versions prior to 4.13.17, 4.14.12 and 4.15.5 with vfs_fruit configured allow out-of-bounds heap read and write via specially crafted extended file attributes. A remote attacker with write access to extended file attributes can execute arbitrary code with the privileges of smbd, typically root.
All versions of Samba prior to 4.15.5 are vulnerable to a malicious client using a server symlink to determine if a file or directory exists in an area of the server file system not exported under the share definition. SMB1 with unix extensions has to be enabled in order for this attack to succeed.
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.
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 flaw was found in the way samba implemented SMB1 authentication. An attacker could use this flaw to retrieve the plaintext password sent over the wire even if Kerberos authentication was required.
All versions of Samba prior to 4.13.16 are vulnerable to a malicious client using an SMB1 or NFS race to allow a directory to be created in an area of the server file system not exported under the share definition. Note that SMB1 has to be enabled, or the share also available via NFS in order for this attack to succeed.
A null pointer de-reference was found in the way samba kerberos server handled missing sname in TGS-REQ (Ticket Granting Server - Request). An authenticated user could use this flaw to crash the samba server.
A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.
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 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.
An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, using the Netlogon Remote Protocol (MS-NRPC). An attacker who successfully exploited the vulnerability could run a specially crafted application on a device on the network.
To exploit the vulnerability, an unauthenticated attacker would be required to use MS-NRPC to connect to a domain controller to obtain domain administrator access.
Microsoft is addressing the vulnerability in a phased two-part rollout. These updates address the vulnerability by modifying how Netlogon handles the usage of Netlog
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 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 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.
All samba versions 4.9.x before 4.9.18, 4.10.x before 4.10.12 and 4.11.x before 4.11.5 have an issue where if it is set with "log level = 3" (or above) then the string obtained from the client, after a failed character conversion, is printed. Such strings can be provided during the NTLMSSP authentication exchange. In the Samba AD DC in particular, this may cause a long-lived process(such as the RPC server) to terminate. (In the file server case, the most likely target, smbd, operates as process-per-client and so a crash there is harmless).
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.