The RPC code generator in Samba 3.x before 3.4.16, 3.5.x before 3.5.14, and 3.6.x before 3.6.4 does not implement validation of an array length in a manner consistent with validation of array memory allocation, which allows remote attackers to execute arbitrary code via a crafted RPC call.

As per upstream samba advisory:

All versions of Samba from 3.5.0 to 4.2.0rc4 are vulnerable to an unexpected code execution vulnerability in the smbd file server daemon.

A malicious client could send packets that may set up the stack in such a way that the freeing of memory in a subsequent anonymous netlogon packet could allow execution of arbitrary code. This code would execute with root privileges.

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).

Heimdal before 7.7.1 allows remote attackers to execute arbitrary code because of an invalid free in the ASN.1 codec used by the Key Distribution Center (KDC).

As per upstream advisory:

All versions of Samba from 4.0.0 onwards are vulnerable to a use after free vulnerability, where a malicious SMB1 request can be used to control the contents of heap memory via a deallocated heap pointer. It is possible this may be used to compromise the SMB server.

rsync 3.1.3-development before 2017-10-24 mishandles archaic checksums, which makes it easier for remote attackers to bypass intended access restrictions. NOTE: the rsync development branch has significant use beyond the rsync developers, e.g., the code has been copied for use in various GitHub projects.

A path traversal vulnerability was identified in Samba when processing client pipe names connecting to Unix domain sockets within a private directory. Samba typically uses this mechanism to connect SMB clients to remote procedure call (RPC) services like SAMR LSA or SPOOLSS, which Samba initiates on demand. However, due to inadequate sanitization of incoming client pipe names, allowing a client to send a pipe name containing Unix directory traversal characters (../). This could result in SMB clients connecting as root to Unix domain sockets outside the private directory. If an attacker or client managed to send a pipe name resolving to an external service using an existing Unix domain socket, it could potentially lead to unauthorized access to the service and consequential adverse events, including compromise or service crashes.

distcc 2.x, as used in XCode 1.5 and others, when not configured to restrict access to the server port, allows remote attackers to execute arbitrary commands via compilation jobs, which are executed by the server without authorization checks.

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.

The Samba vfsfruit 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 vfsfruit 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.

As per upstream report:

In order to avoid issues like CVE-2020-25717 AD Kerberos accepting services need access to unique, and ideally long-term stable identifiers of a user to perform authorization.

The AD PAC provides this, but the most useful information is kept in a buffer which is NDR encoded, which means that so far in Free Software only Samba and applications which use Samba components under the hood like FreeIPA and SSSD decode PAC.

Recognising that the issues seen in Samba are not unique, Samba now provides an extension to UPNDNSINFO, a component of the AD PAC, in a way that can be parsed using basic pointer handling.

From this, future non-Samba based Kerberised applications can easily obtain the user's SID, in the same packing as objectSID in LDAP, confident that the ticket represents a specific user, not matter subsequent renames.

This will allow such non-Samba applications to avoid confusing one Kerberos user for another, even if they have the same string name (due to the gap between time of ticket printing by the KDC and time of ticket acceptance).

As per upstream report:

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 sessioninfo'.

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.

A flaw was found in Samba. The KDC accepts kpasswd requests encrypted with any key known to it. By encrypting forged kpasswd requests with its own key, a user can change other users' passwords, enabling full domain takeover.

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.

As per upstream advisory:

Samba as an Active Directory Domain Controller has to take care to protect a number of sensitive attributes, and to follow a security model from Active Directory that relies totally on the intersection of NT security descriptors and the underlying X.500 Directory Access Protocol (as then expressed in LDAP) schema constraints for security.

Some attributes in Samba AD are sensitive, they apply to one object but protect others.

Users who can set msDS-AllowedToDelegateTo can become any user in the domain on the server pointed at by this list. Likewise in a domain mixed with Microsoft Windows, Samba's lack of protection of sidHistory would be a similar issue.

This would be limited to users with the right to create users or modify them (typically those who created them), however, due to other flaws, all users are able to create new user objects.

A flaw was found in Samba. The security vulnerability occurs when KDC and the kpasswd service share a single account and set of keys, allowing them to decrypt each other's tickets. A user who has been requested to change their password, can exploit this flaw to obtain and use tickets to other services.

As per samba upstream advisory:

The Samba AD DC includes checks when adding service principals names (SPNs) to an account to ensure that SPNs do not alias with those already in the database. Some of these checks are able to be bypassed if an account modification re-adds an SPN that was previously present on that account, such as one added when a computer is joined to a domain.

An attacker who has the ability to write to an account can exploit this to perform a denial-of-service attack by adding an SPN that matches an existing service. Additionally, an attacker who can intercept traffic can impersonate existing services, resulting in a loss of confidentiality and integrity.

PAC parsing in MIT Kerberos 5 (aka krb5) before 1.19.4 and 1.20.x before 1.20.1 has integer overflows that may lead to remote code execution (in KDC, kadmind, or a GSS or Kerberos application server) on 32-bit platforms (which have a resultant heap-based buffer overflow), and cause a denial of service on other platforms. This occurs in krb5pacparse in lib/krb5/krb/pac.c. Heimdal before 7.7.1 has "a similar bug."

A flaw was found in samba versions 4.0.0 to 4.5.2. The Samba routine ndrpulldnspname contains an integer wrap problem, leading to an attacker-controlled memory overwrite. ndrpulldnspname parses data from the Samba Active Directory ldb database. Any user who can write to the dnsRecord attribute over LDAP can trigger this memory corruption. By default, all authenticated LDAP users can write to the dnsRecord attribute on new DNS objects. This makes the defect a remote privilege escalation.

DISPUTED A vulnerability classified as problematic has been found in ppp. Affected is the function dumpppp of the file pppdump/pppdump.c of the component pppdump. The manipulation of the argument spkt.buf/rpkt.buf leads to improper validation of array index. The real existence of this vulnerability is still doubted at the moment. The name of the patch is a75fb7b198eed50d769c80c36629f38346882cbf. It is recommended to apply a patch to fix this issue. VDB-216198 is the identifier assigned to this vulnerability. NOTE: pppdump is not used in normal process of setting up a PPP connection, is not installed setuid-root, and is not invoked automatically in any scenario.

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.

Samba 4.0.x before 4.0.24, 4.1.x before 4.1.16, and 4.2.x before 4.2rc4, when an Active Directory Domain Controller (AD DC) is configured, allows remote authenticated users to set the LDB userAccountControl UFSERVERTRUSTACCOUNT bit, and consequently gain privileges, by leveraging delegation of authority for user-account or computer-account creation.

smbd in Samba 3.0.29 through 3.2.4 might allow remote attackers to read arbitrary memory and cause a denial of service via crafted (1) trans, (2) trans2, and (3) nttrans requests, related to a "cut&paste error" that causes an improper bounds check to be performed.

Heap-based buffer overflow in the dcerpcreadncacnpacketdone function in librpc/rpc/dcerpcutil.c in winbindd in Samba 3.x before 3.6.22, 4.0.x before 4.0.13, and 4.1.x before 4.1.3 allows remote AD domain controllers to execute arbitrary code via an invalid fragment length in a DCE-RPC packet.

A flaw was found in Samba. Samba AD users can cause the server to access uninitialized data with an LDAP add or modify the request, usually resulting in a segmentation fault.

Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. In krb5extractticket() the KDC-REP service name must be obtained from the encrypted version stored in 'encpart' instead of the unencrypted version stored in 'ticket'. Use of the unencrypted version provides an opportunity for successful server impersonation and other attacks. NOTE: this CVE is only for Heimdal and other products that embed Heimdal code; it does not apply to other instances in which this part of the Kerberos 5 protocol specification is violated.

A flaw was found in the way Samba handled Any Batched (AndX) request packets. A malicious request could cause smbd to enter an infinite recursion and overflow heap-based buffer during recursive calls. This can be triggered by an unauthenticated attacker, resulting in smbd child process crash or possibly code execution.

As reported in the upstream advisory and bugzilla [1]:

All current versions of Samba 4.x.x are vulnerable to a remote code execution vulnerability in the nmbd NetBIOS name services daemon.

A malicious browser can send packets that may overwrite the heap of the target nmbd NetBIOS name services daemon. It may be possible to use this to generate a remote code execution vulnerability as the superuser (root).

Patches are available for 4.1.x [2] and 4.0.x [3].

[1] https://bugzilla.samba.org/showbug.cgi?id=10735 [2] https://git.samba.org/?p=samba.git;a=commitdiff;h=e6a848630da3ba958c442438ea131c99fa088605 [3] https://git.samba.org/?p=samba.git;a=commitdiff;h=fb1d325d96dfe9bc2e9c4ec46ad4c55e8f18f4a2

External References:

https://www.samba.org/samba/security/CVE-2014-3560

Statement:

This issue did not affect the versions of samba or samba3x as shipped with Red Hat Enterprise Linux 5, and the versions of samba as shipped with Red Hat Enterprise Linux 6, as it only affected Samba 4.0.0 and higher.

The fix in 4.6.16, 4.7.9, 4.8.4 and 4.9.7 for CVE-2018-10919 Confidential attribute disclosure vi LDAP filters was insufficient and an attacker may be able to obtain confidential BitLocker recovery keys from a Samba AD DC.

Samba does not validate the Validated-DNS-Host-Name right for the dNSHostName attribute which could permit unprivileged users to write it.