CVE-2019-5023 : Security Advisory and Response

A vulnerability has been found in the grsecurity PaX patch, affecting versions of PaX and grsecurity. The vulnerability can lead to memory leakage and potential system crashes when exploited.

Understanding CVE-2019-5023

This CVE involves a vulnerability in the read_kmem function within the grsecurity PaX patch, impacting specific versions of PaX and grsecurity.

What is CVE-2019-5023?

The vulnerability in the read_kmem function of PaX allows for memory leakage and potential system crashes when triggered by an attacker using an invalid address.

The Impact of CVE-2019-5023

The vulnerability poses a medium severity risk with a CVSS base score of 5.9. It requires local access to exploit and can result in high availability impact.

Technical Details of CVE-2019-5023

This section provides technical details about the vulnerability.

Vulnerability Description

The read_kmem function in PaX fails to release a temporary buffer when an invalid address is provided, leading to memory leakage and system instability.

Affected Systems and Versions

PaX versions: pax-linux-4.9.8-test1 to 4.9.24-test7
Grsecurity official versions: grsecurity-3.1-4.9.8-201702060653 to grsecurity-3.1-4.9.24-201704252333
Grsecurity unofficial versions: v4.9.25-unofficialgrsec to v4.9.74-unofficialgrsec

Exploitation Mechanism

To exploit this vulnerability, an attacker must trigger a read to /dev/kmem using an invalid address, causing the read_kmem function to fail in releasing the temporary buffer.

Mitigation and Prevention

Protect your systems from CVE-2019-5023 with the following steps:

Immediate Steps to Take

Apply patches provided by the vendor to address the vulnerability.
Monitor for any unusual activities on the system that could indicate exploitation.

Long-Term Security Practices

Regularly update and patch your systems to prevent known vulnerabilities.
Implement access controls to limit exposure to potential attackers.

Patching and Updates

Stay informed about security updates and apply them promptly to mitigate risks associated with known vulnerabilities.