CVE-2023-31315: AMD Processor MSR Validation RCE Flaw

CVE-2023-31315 Overview

Improper validation in a model specific register (MSR) could allow a malicious program with ring0 access to modify SMM configuration while SMI lock is enabled, potentially leading to arbitrary code execution.

Critical Impact

This vulnerability permits local attackers to execute arbitrary code with elevated privileges by exploiting MSR validation issues.

Affected Products

• Not Available
• Not Available
• Not Available

Discovery Timeline

• 2024-08-12 - CVE CVE-2023-31315 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-31315

Vulnerability Analysis

This vulnerability arises from improper validation within MSR when handling certain configurations of SMM, allowing an attacker with ring0 access to modify SMM configurations inappropriately.

Root Cause

The root cause is the inadequate validation of parameters within the MSR which affects SMM configurations.

Attack Vector

The attack vector is local, requiring the attacker to have ring0 access to the system.

// Example exploitation code (sanitized)
void exploit() {
    __asm__("mov eax, 0x1A2; wrmsr;");
}

Detection Methods for CVE-2023-31315

Indicators of Compromise

• Unusual modifications to MSR settings
• Unexpected SMM configuration changes
• Elevated ring0 access logs without proper authentication

Detection Strategies

Utilize monitoring tools to alert on unauthorized modifications to MSR or unexpected SMM configurations.

Monitoring Recommendations

Implement kernel-level monitoring for MSR write operations and SMM configuration changes to detect exploitation attempts.

How to Mitigate CVE-2023-31315

Immediate Actions Required

• Review and ensure proper MSR validation logic is in place
• Restrict ring0 access to trusted applications only
• Monitor and log all access to SMM configurations

Patch Information

For patch details, refer to the official AMD advisory at AMD Bulletin.

Workarounds

Disable non-essential SMM capabilities and ensure hardware mitigation features are enabled.

# Configuration example
echo "Disabling non-essential SMM capabilities..."
# Example command placeholder
echo 0 > /sys/module/smm/parameters/disable