SB2020121815 - Red Hat Enterprise Linux 7 update for samba
Published: December 18, 2020 Updated: January 7, 2024
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 secuirty vulnerabilities.
1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-1472)
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)
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)
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.