SB2021120637 - Ubuntu update for samba
Published: December 6, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Improper access control (CVE-ID: CVE-2016-2124)
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to SMB1 client connections can be downgraded to plaintext authentication. A remote attacker can perform a man-in-the-middle attack and downgrade a negotiated SMB1 client connection and its capabitilities.
2) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-25717)
The vulnerability allows a remote attacker to escalate privileges on the system.
The vulnerability exists due to the Windows Active Directory (AD) domains have by default a feature to allow users to create computer accounts. A remote authenticated attacker can create such account with elevated privileges on the system.
3) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-25722)
The vulnerability allows a remote authenticated attacker to escalate privileges on the system.
The vulnerability exists due to application does not properly impose security restrictions, which leads to security restrictions bypass and privilege escalation.
4) NULL pointer dereference (CVE-ID: CVE-2021-3671)
The vulnerability allows a remote user to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error in the way samba kerberos server handles missing sname attribute in TGS-REQ (Ticket Granting Server - Request). A remote authenticated user can send a specially crafted request to the samba server and perform a denial of service (DoS) attack.
Remediation
Install update from vendor's website.