CVE-2017-7374 : Exploit Details and Defense Strategies

A vulnerability in the Linux kernel before version 4.10.7, specifically in the fs/crypto/ component, has been identified. This vulnerability, known as a use-after-free vulnerability, could potentially be exploited by local users to either cause a denial of service (by dereferencing a NULL pointer) or gain elevated privileges. This can be achieved by revoking keyring keys that are currently being used for ext4, f2fs, or ubifs encryption. As a result, the premature freeing of cryptographic transform objects occurs, leading to these security implications.

Understanding CVE-2017-7374

This section provides insights into the impact and technical details of CVE-2017-7374.

What is CVE-2017-7374?

The vulnerability in the Linux kernel before version 4.10.7, specifically in the fs/crypto/ component, allows local users to exploit a use-after-free vulnerability, potentially leading to a denial of service or privilege escalation.

The Impact of CVE-2017-7374

Local users can exploit the vulnerability to cause a denial of service or gain elevated privileges.
Revoking keyring keys used for ext4, f2fs, or ubifs encryption can trigger premature freeing of cryptographic transform objects.

Technical Details of CVE-2017-7374

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The use-after-free vulnerability in fs/crypto/ in the Linux kernel before 4.10.7 allows local users to cause a denial of service or potentially gain privileges by revoking keyring keys used for ext4, f2fs, or ubifs encryption.

Affected Systems and Versions

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Exploitation Mechanism

Local users can exploit the vulnerability by revoking keyring keys used for specific encryption, leading to premature freeing of cryptographic transform objects.

Mitigation and Prevention

Protecting systems from CVE-2017-7374 requires immediate steps and long-term security practices.

Immediate Steps to Take

Apply relevant patches and updates to the Linux kernel to mitigate the vulnerability.
Monitor and restrict access to keyring keys to prevent unauthorized revocation.

Long-Term Security Practices

Implement the principle of least privilege to limit user access rights.
Regularly update and patch systems to address known vulnerabilities.

Patching and Updates

Ensure timely installation of security patches for the Linux kernel to address the use-after-free vulnerability in fs/crypto/.