CVE-2020-15436 Explained : Impact and Mitigation

A use-after-free vulnerability in fs/block_dev.c in the Linux kernel before 5.8 allows local users to gain privileges or cause a denial of service by leveraging improper access to a certain error field.

Understanding CVE-2020-15436

This CVE identifies a specific vulnerability in the Linux kernel that can be exploited by local users to escalate privileges or disrupt services.

What is CVE-2020-15436?

The CVE-2020-15436 is a use-after-free vulnerability found in the Linux kernel before version 5.8. This flaw enables local users to exploit improper access to an error field, potentially leading to privilege escalation or denial of service attacks.

The Impact of CVE-2020-15436

The vulnerability poses a significant risk as it allows attackers with local access to potentially gain elevated privileges or disrupt system services, compromising the overall security and stability of affected systems.

Technical Details of CVE-2020-15436

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability resides in fs/block_dev.c in the Linux kernel before version 5.8, where improper access to a specific error field can result in a use-after-free scenario, enabling malicious actors to exploit the system.

Affected Systems and Versions

Product: Linux kernel
Vendor: Not applicable
Versions: 5.7 (verified), possibly others 4.18

Exploitation Mechanism

The vulnerability can be exploited by local users through leveraging improper access to the error field in fs/block_dev.c, allowing them to execute privilege escalation or denial of service attacks.

Mitigation and Prevention

Protecting systems from CVE-2020-15436 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply relevant security patches provided by the Linux kernel maintainers promptly.
Monitor system logs for any suspicious activities that could indicate exploitation attempts.

Long-Term Security Practices

Implement the principle of least privilege to restrict user access and minimize the impact of potential vulnerabilities.
Conduct regular security audits and vulnerability assessments to proactively identify and address security weaknesses.

Patching and Updates

Regularly update the Linux kernel to the latest stable version to ensure that known vulnerabilities, including CVE-2020-15436, are patched and system security is maintained.