CVE-2018-20421 Explained : Impact and Mitigation

Go Ethereum (geth) version 1.8.19 has a vulnerability that allows attackers to disrupt the system by consuming excessive memory through a specific manipulation technique.

Understanding CVE-2018-20421

What is CVE-2018-20421?

The vulnerability in Go Ethereum (geth) 1.8.19 enables attackers to cause a denial of service by manipulating the length of a dynamic array in memory and writing data to a specific memory location using a high index number.

The Impact of CVE-2018-20421

This vulnerability can lead to a system disruption due to memory consumption, potentially affecting the availability and performance of the system.

Technical Details of CVE-2018-20421

Vulnerability Description

Attackers can exploit this vulnerability by rewriting the length of a dynamic array in memory and writing data to a single memory location with a large index number, using specific commands like "assembly { mstore }" followed by assignments like "c[0xC800000] = 0xFF".

Affected Systems and Versions

Product: Go Ethereum (geth) 1.8.19
Vendor: N/A
Version: N/A

Exploitation Mechanism

The exploitation involves modifying the length of a dynamic array in memory and writing data to a specific memory location with a high index number, causing memory consumption and system disruption.

Mitigation and Prevention

Immediate Steps to Take

Update to a patched version of Go Ethereum to mitigate the vulnerability.
Monitor system memory usage for any unusual spikes that could indicate exploitation.

Long-Term Security Practices

Regularly update software and apply security patches to prevent known vulnerabilities.
Implement proper access controls and monitoring to detect and respond to suspicious activities.

Patching and Updates

Ensure timely installation of security updates and patches provided by the software vendor to address vulnerabilities like CVE-2018-20421.