SB2021052030 - Red Hat Enterprise Linux 8 update for samba

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Main Vulnerability Database SB2021052030

SB2021052030 - Red Hat Enterprise Linux 8 update for samba

Published: May 20, 2021 Updated: January 7, 2024

Security Bulletin ID SB2021052030
CSH Severity
High
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 33% Medium 33% Low 33%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-1472)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber


The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions in Netlogon. A remote non-authenticated attacker can use MS-NRPC to connect to a domain controller to obtain domain administrator access. This vulnerability was dubbed ZeroLogon.


2) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-14318)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote user to gain access to sensitive information.

The vulnerability exists due to the way "ChangeNotify" concept for SMB1/2/3 protocols was implemented in Samba. A missing permissions check on a directory handle requesting ChangeNotify means that a client with a directory handle open only for FILE_READ_ATTRIBUTES (minimal access rights) could be used to obtain change notify replies from the server. These replies contain information that should not be available to directory handles open for FILE_READ_ATTRIBUTE only. A local unprivileged user can abuse this lack of permissions check to obtain information about file changes.


3) NULL pointer dereference (CVE-ID: CVE-2020-14323)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error when processing requests in winbind in Samba. A remote user can send specially crafted request to winbind daemon, trigger a NULL pointer dereference error and crash it.


Remediation

Install update from vendor's website.

References