CVE-2017-18221 Explained : Impact and Mitigation

A vulnerability in the Linux kernel versions prior to 4.11.4 could allow local users to launch a denial of service attack, resulting in NR_MLOCK accounting corruption.

Understanding CVE-2017-18221

This CVE identifies a specific flaw in the Linux kernel that could be exploited by local users to cause a denial of service attack.

What is CVE-2017-18221?

The __munlock_pagevec function in the mm/mlock.c file within Linux kernel versions before 4.11.4 could be manipulated by local users to generate a denial of service attack that leads to NR_MLOCK accounting corruption. This manipulation is achieved through the mlockall and munlockall system calls.

The Impact of CVE-2017-18221

The vulnerability could result in a denial of service attack, causing NR_MLOCK accounting corruption within affected systems.

Technical Details of CVE-2017-18221

This section provides more detailed technical insights into the CVE.

Vulnerability Description

The __munlock_pagevec function in mm/mlock.c in the Linux kernel before 4.11.4 allows local users to cause a denial of service (NR_MLOCK accounting corruption) via crafted use of mlockall and munlockall system calls.

Affected Systems and Versions

Affected Systems: Linux kernel versions prior to 4.11.4
Affected Function: __munlock_pagevec in mm/mlock.c

Exploitation Mechanism

The vulnerability can be exploited by local users through manipulation of the mlockall and munlockall system calls.

Mitigation and Prevention

Protecting systems from this vulnerability requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply relevant patches and updates to the Linux kernel to mitigate the vulnerability.
Monitor system logs for any unusual activities related to mlockall and munlockall system calls.

Long-Term Security Practices

Implement the principle of least privilege to restrict unnecessary access to system functions.
Regularly update and patch the Linux kernel to address known vulnerabilities.

Patching and Updates

Stay informed about security advisories and updates from Linux kernel maintainers.
Ensure timely application of patches to keep systems secure.