CVE-2023-4091

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.

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

Security Fix(es):

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.(CVE-2023-4091)

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.(CVE-2023-42669)

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

Security Fix(es):

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.(CVE-2023-4091)

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.(CVE-2023-42669)

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

Security Fix(es):

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.(CVE-2023-4091)

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.(CVE-2023-42669)

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

Security Fix(es):

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.(CVE-2023-3961)

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.(CVE-2023-4091)

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.(CVE-2023-42669)

A flaw was found in Samba. It is susceptible to a vulnerability where multiple incompatible RPC listeners can be initiated, causing disruptions in the AD DC service. When Samba's RPC server experiences a high load or unresponsiveness, servers intended for non-AD DC purposes (for example, NT4-emulation "classic DCs") can erroneously start and compete for the same unix domain sockets. This issue leads to partial query responses from the AD DC, causing issues such as "The procedure number is out of range" when using tools like Active Directory Users. This flaw allows an attacker to disrupt AD DC services.(CVE-2023-42670)

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

Security Fix(es):

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.(CVE-2023-3961)

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.(CVE-2023-4091)

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This vulnerability stems from an RPC function that can be blocked indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task.(CVE-2023-42669)

A flaw was found in Samba. It is susceptible to a vulnerability where multiple incompatible RPC listeners can be initiated, causing disruptions in the AD DC service. When Samba's RPC server experiences a high load or unresponsiveness, servers intended for non-AD DC purposes (for example, NT4-emulation "classic DCs") can erroneously start and compete for the same unix domain sockets. This issue leads to partial query responses from the AD DC, causing issues such as "The procedure number is out of range" when using tools like Active Directory Users. This flaw allows an attacker to disrupt AD DC services.(CVE-2023-42670)

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.

Samba is an open-source implementation of the Server Message Block (SMB) protocol and the related Common Internet File System (CIFS) protocol, which allow PC-compatible machines to share files, printers, and various information.

Security Fix(es):

• samba: smbd allows client access to unix domain sockets on the file system as root (CVE-2023-3961)
• samba: SMB clients can truncate files with read-only permissions (CVE-2023-4091)
• samba: "rpcecho" development server allows denial of service via sleep() call on AD DC (CVE-2023-42669)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Samba is an open-source implementation of the Server Message Block (SMB) protocol and the related Common Internet File System (CIFS) protocol, which allow PC-compatible machines to share files, printers, and various information.

Security Fix(es):

• samba: smbd allows client access to unix domain sockets on the file system as root (CVE-2023-3961)
• samba: SMB clients can truncate files with read-only permissions (CVE-2023-4091)
• samba: "rpcecho" development server allows denial of service via sleep() call on AD DC (CVE-2023-42669)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

• CVE-2023-4091: fix file truncation issue in acl_xattr module by enforcing kernel file system permissions checks, use open_access_mask for access check in open_file() in smbd
• CVE-2023-34967: fix type confusion vulnerability in mdssvc RPC service by implementing proper type checking in dalloc_value_for_key function
• CVE-2023-34968: fix path disclosure vulnerability by sanitizing search query results
• CVE-2023-42669: disable the rpcecho server

• Fix CVE-2023-4091: fix vulnerability that allows SMB clients to truncate files, even with read-only permissions for certain acl_xattr settings.

• CVE-2023-4091: fix open_file() access check that allowed a client with read-only share access to truncate files via SMB2 OVERWRITE; the access check now uses open_access_mask instead of the requested access_mask

• CVE-2023-4091: fix open_file() access check that allowed a client with read-only share access to truncate files via SMB2 OVERWRITE; the access check now uses open_access_mask instead of the requested access_mask

• Rebase onto RHEL samba-4.14.5-9.el8_5: CVE-2021-44142, the CVE-2020-25717 username map script regression, the domain-join segfault and the dangling symlink directory deletion fixes are now provided by the base.
• Re-apply TuxCare ELS security backports on the new base:
• CVE-2022-32742: fix server memory information leak via SMB1
• CVE-2022-38023: avoid weak rc4-hmac encryption algorithm for the Netlogon RPC
• CVE-2022-1615: util/genrand: don't ignore errors in random number generation
• CVE-2022-2127: fix out-of-bounds read triggered by a malicious request
• CVE-2023-34966: fix infinite loop vulnerability in mdssvc RPC service
• CVE-2023-3961: fix a path traversal out of the socket directory
• CVE-2023-4091: fix file truncation issue in acl_xattr module
• CVE-2023-34967: fix type confusion vulnerability in mdssvc RPC service
• CVE-2023-34968: fix path disclosure vulnerability in mdssvc
• CVE-2023-42669: disable the rpcecho server
• CVE-2026-4480: escape shell metacharacters in the client-controlled print job name before substituting it into "print command" via %J

This update fixes the security issues below.

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. (CVE-2023-3961)

A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions. (CVE-2023-4091)

A vulnerability was found in Samba's "rpcecho" development server, a non-Windows RPC server used to test Samba's DCE/RPC stack elements. This indefinitely. The issue arises because the "rpcecho" service operates with only one worker in the main RPC task, allowing calls to the "rpcecho" server to be blocked for a specified time, causing service disruptions. This disruption is triggered by a "sleep()" call in the "dcesrv_echo_TestSleep()" function under specific conditions. Authenticated users or attackers can exploit this vulnerability to make calls to the "rpcecho" server, requesting it to block for a specified duration, effectively disrupting most services and leading to a complete denial of service on the AD DC. The DoS affects all other services as "rpcecho" runs in the main RPC task. (CVE-2023-42669)

Apart from the new version, a Recommends for cifs-client was added in samba-client for https://bugs.mageia.org/show_bug.cgi?id=28606

These are all security issues fixed in the ctdb-4.19.1+git.312.c912b3d2ef6-1.1 package on the GA media of openSUSE Tumbleweed.

This update for samba fixes the following issues:

• CVE-2023-4091: Fixed a bug where a client can truncate file with read-only permissions. (bsc#1215904)

This update for samba fixes the following issues:

• CVE-2023-4091: Fixed a bug where a client can truncate file with read-only permissions. (bsc#1215904)
• CVE-2023-42669: Fixed a bug in 'rpcecho' development server which allows Denial of Service via sleep() call on AD DC. (bsc#1215905)
• CVE-2023-42670: Fixed the procedure number which was out of range when starting Active Directory Users and Computers. (bsc#1215906)
• CVE-2023-3961: Fixed an unsanitized client pipe name passed to local_np_connect(). (bsc#1215907)
• CVE-2023-4154: Fixed a bug in dirsync which allows SYSTEM access with only 'GUID_DRS_GET_CHANGES' right. (bsc#1215908)

This update for samba fixes the following issues:

• CVE-2023-4091: Fixed a bug where a client can truncate file with read-only permissions. (bsc#1215904)
• CVE-2023-42669: Fixed a bug in 'rpcecho' development server which allows Denial of Service via sleep() call on AD DC. (bso#1215905)
• CVE-2023-4154: Fixed a bug in dirsync which allows SYSTEM access with only 'GUID_DRS_GET_CHANGES' right. (bsc#1215908)

This update for samba fixes the following issues:

• CVE-2023-4091: Fixed a bug where a client can truncate file with read-only permissions. (bsc#1215904)
• CVE-2023-42669: Fixed a bug in 'rpcecho' development server which allows Denial of Service via sleep() call on AD DC. (bso#1215905)
• CVE-2023-4154: Fixed a bug in dirsync which allows SYSTEM access with only 'GUID_DRS_GET_CHANGES' right. (bsc#1215908)

Sri Nagasubramanian discovered that the Samba acl_xattr VFS module incorrectly handled read-only files. When Samba is configured to ignore system ACLs, a remote attacker could possibly use this issue to truncate read-only files. (CVE-2023-4091)

Andrew Bartlett discovered that Samba incorrectly handled the DirSync control. A remote attacker with an RODC DC account could possibly use this issue to obtain all domain secrets. (CVE-2023-4154)

Andrew Bartlett discovered that Samba incorrectly handled the rpcecho development server. A remote attacker could possibly use this issue to cause Samba to stop responding, resulting in a denial of service. (CVE-2023-42669)

Kirin van der Veer discovered that Samba incorrectly handled certain RPC service listeners. A remote attacker could possibly use this issue to cause Samba to start multiple incompatible RPC listeners, resulting in a denial of service. This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04. (CVE-2023-42670)