CVE-2019-12436 Explained : Impact and Mitigation

Samba before version 4.10.5, specifically 4.10.x, has a vulnerability that can lead to a Denial of Service attack on the AD DC LDAP server. This CVE occurs due to a NULL pointer dereference when an attacker uses the paged search control. It's crucial to highlight that the attacker must already possess directory read access to exploit this vulnerability.

Understanding CVE-2019-12436

This section provides insights into the nature and impact of the CVE-2019-12436 vulnerability.

What is CVE-2019-12436?

CVE-2019-12436 is a vulnerability in Samba versions before 4.10.5 that can result in a Denial of Service attack on the AD DC LDAP server. The exploit involves a NULL pointer dereference triggered by an attacker utilizing the paged search control.

The Impact of CVE-2019-12436

The vulnerability allows an attacker to cause a Denial of Service on the AD DC LDAP server by exploiting a NULL pointer dereference. However, successful exploitation requires the attacker to have directory read access beforehand.

Technical Details of CVE-2019-12436

This section delves into the technical aspects of the CVE-2019-12436 vulnerability.

Vulnerability Description

Samba 4.10.x before 4.10.5 experiences a NULL pointer dereference, leading to a Denial of Service on the AD DC LDAP server. The vulnerability is triggered when an attacker uses the paged search control, requiring prior directory read access.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: All versions before 4.10.5

Exploitation Mechanism

The vulnerability is exploited by an attacker who uses the paged search control, triggering a NULL pointer dereference. Successful exploitation necessitates the attacker to have directory read access.

Mitigation and Prevention

Learn how to mitigate and prevent the CVE-2019-12436 vulnerability.

Immediate Steps to Take

Update Samba to version 4.10.5 or later to patch the vulnerability.
Restrict access to the affected systems to authorized personnel only.
Monitor network traffic for any suspicious activity.

Long-Term Security Practices

Regularly update and patch all software and systems to prevent vulnerabilities.
Implement strong access controls and authentication mechanisms.
Conduct security training for employees to raise awareness of potential threats.

Patching and Updates

Ensure timely installation of security patches and updates to mitigate the CVE-2019-12436 vulnerability.