CVE-2018-18281 Explained : Impact and Mitigation

Linux kernel vulnerability affecting mremap() system call.

Understanding CVE-2018-18281

Linux kernel vulnerability allowing access to physical pages after release.

What is CVE-2018-18281?

Since Linux kernel version 3.2, the mremap() syscall may leave a stale TLB entry, allowing unauthorized access to physical pages.

The Impact of CVE-2018-18281

The vulnerability could permit access to physical memory even after it has been released and reused.

Technical Details of CVE-2018-18281

Linux kernel vulnerability affecting mremap() system call.

Vulnerability Description

The mremap() system call in Linux kernel versions 3.2 and above may lead to a persistent TLB entry, enabling unauthorized access to physical pages.

Affected Systems and Versions

Affected systems: Linux kernel versions 3.2 and above
Fixed versions: 4.9.135, 4.14.78, 4.18.16, 4.19

Exploitation Mechanism

TLB flushes after releasing pagetable locks may not occur timely, leading to a window of opportunity for unauthorized access.

Mitigation and Prevention

Protect systems from CVE-2018-18281 exploitation.

Immediate Steps to Take

Apply patches provided by Linux kernel updates.
Monitor for any unauthorized access to physical memory.

Long-Term Security Practices

Regularly update the Linux kernel to the latest secure versions.
Implement strict access controls and monitoring mechanisms.
Conduct regular security audits and assessments.

Patching and Updates

Update to fixed kernel versions: 4.9.135, 4.14.78, 4.18.16, 4.19