CVE-2020-27174 : Exploit Details and Defense Strategies

Amazon AWS Firecracker before 0.21.3 and 0.22.x before 0.22.1 is affected by a vulnerability where the serial console buffer can lead to memory leaks, potentially causing excessive memory usage.

Understanding CVE-2020-27174

This CVE describes a memory leak issue in Amazon AWS Firecracker that can result in unbounded memory allocation when data is sent to the standard input.

What is CVE-2020-27174?

In Amazon AWS Firecracker versions before 0.21.3 and 0.22.x before 0.22.1, a flaw allows the serial console buffer to consume memory without limits, leading to a memory leak on the microVM emulation thread.

The Impact of CVE-2020-27174

The vulnerability can cause the microVM emulation thread to occupy more memory than intended on the host, potentially affecting system performance and stability.

Technical Details of CVE-2020-27174

Amazon AWS Firecracker vulnerability details.

Vulnerability Description

The serial console buffer in Amazon AWS Firecracker can grow its memory usage without limit, resulting in a memory leak on the microVM emulation thread.

Affected Systems and Versions

Amazon AWS Firecracker versions before 0.21.3
Amazon AWS Firecracker 0.22.x before 0.22.1

Exploitation Mechanism

When data is sent to the standard input, the serial console buffer in Amazon AWS Firecracker can grow indefinitely, leading to memory leaks.

Mitigation and Prevention

Steps to address and prevent the CVE-2020-27174 vulnerability.

Immediate Steps to Take

Update Amazon AWS Firecracker to version 0.21.3 or 0.22.1 to mitigate the memory leak issue.
Monitor memory usage on the host to detect any abnormal increases.

Long-Term Security Practices

Regularly update and patch Amazon AWS Firecracker to ensure the latest security fixes are applied.
Implement memory usage monitoring and limits to prevent excessive resource consumption.

Patching and Updates

Apply patches provided by Amazon AWS Firecracker promptly to address the memory leak vulnerability.