Alpine: multiple ldb packages, multiple samba packages, pam-winbind: security update to 4.18.8-r0

critical Tenable Cloud Security Plugin ID 424511

Description

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

- 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 design flaw was found in Samba's DirSync control implementation, which exposes passwords and secrets in
Active Directory to privileged users and Read-Only Domain Controllers (RODCs). This flaw allows RODCs and
users possessing the GET_CHANGES right to access all attributes, including sensitive secrets and
passwords. Even in a default setup, RODC DC accounts, which should only replicate some passwords, can gain
access to all domain secrets, including the vital krbtgt, effectively eliminating the RODC / DC
distinction. Furthermore, the vulnerability fails to account for error conditions (fail open), like out-
of-memory situations, potentially granting access to secret attributes, even under low-privileged attacker
influence. (CVE-2023-4154)

- 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)

Plugin Details

Severity: Critical

ID: 424511

Version: Revision 1.8

Type: Local

Family: Alpine Linux Local Security Checks

Published: 4/4/2025

Updated: 7/2/2026

Supported Sensors: Agentless Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.58

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2023-3961

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 10/10/2023

Reference Information

CVE: CVE-2023-3961, CVE-2023-4091, CVE-2023-4154, CVE-2023-42669, CVE-2023-42670

IAVA: 2023-A-0535

Detections

Analytics