CVE-2022-40246 Explained : Impact and Mitigation

A critical arbitrary write vulnerability in the SbPei module can lead to arbitrary code execution during the PEI phase, potentially resulting in memory disclosure and bypassing of security boundaries.

Understanding CVE-2022-40246

This CVE-2022-40246 vulnerability affects the Aptio product by AMI, version 5.x. It was discovered by the Binarly efiXplorer team and publicly disclosed on August 11, 2022.

What is CVE-2022-40246?

The vulnerability allows an attacker to write one byte at an arbitrary address during the PEI phase, specifically during the S3 resume boot mode. This can influence subsequent boot stages, bypass mitigations, disclose physical memory contents, discover secrets from Virtual Machines (VMs), and bypass memory isolation and confidential computing boundaries. An attacker could also craft a payload to inject into the SMRAM memory.

The Impact of CVE-2022-40246

The impact of this vulnerability is severe, as it can lead to arbitrary code execution, data disclosure, and compromise of sensitive information stored in memory. Successful exploitation can result in serious security breaches and compromise the integrity of the system.

Technical Details of CVE-2022-40246

The technical details of CVE-2022-40246 are as follows:

Vulnerability Description

The vulnerability arises from an arbitrary write capability during the PEI phase, enabling attackers to manipulate memory contents and execute arbitrary code, potentially compromising system integrity.

Affected Systems and Versions

The vulnerability affects the AMI Aptio product version 5.x specifically. Systems running this version are at risk of exploitation if not promptly addressed.

Exploitation Mechanism

Attackers exploit the vulnerability by writing one byte to an arbitrary address during the PEI phase in S3 resume boot mode, allowing them to manipulate subsequent boot stages and execute malicious code.

Mitigation and Prevention

To mitigate the risks associated with CVE-2022-40246, it is crucial to take immediate action and implement necessary security measures.

Immediate Steps to Take

Organizations should apply security patches provided by the vendor promptly to remediate the vulnerability.
Enhanced monitoring and detection mechanisms should be deployed to detect any unauthorized memory manipulations or code execution attempts.

Long-Term Security Practices

Regular security assessments and audits should be conducted to identify and address potential vulnerabilities proactively.
Employee training and awareness programs can help in recognizing and mitigating security threats effectively.

Patching and Updates

Ensure that systems are regularly updated with the latest security patches and firmware updates to prevent exploitation of known vulnerabilities.
Maintain a robust incident response plan to effectively respond to security incidents and minimize their impact.