CVE-2020-26264 : Exploit Details and Defense Strategies

Go Ethereum, or "Geth", is the official Golang implementation of the Ethereum protocol. In Geth before version 1.9.25, a denial-of-service vulnerability can make a LES server crash via a malicious GetProofsV2 request from a connected LES client. This vulnerability only affects users explicitly enabling LES server; disabling LES prevents the exploit. The vulnerability was patched in version 1.9.25.

Understanding CVE-2020-26264

This CVE involves a denial-of-service vulnerability in Go Ethereum (Geth) that can lead to a crash in the LES server.

What is CVE-2020-26264?

CVE-2020-26264 is a vulnerability in Go Ethereum (Geth) versions prior to 1.9.25 that allows a malicious GetProofsV2 request to cause a denial-of-service attack on a connected LES server.

The Impact of CVE-2020-26264

The vulnerability has a CVSS base score of 6.5, with a medium severity rating. It can result in a high impact on availability, potentially leading to service disruption.

Technical Details of CVE-2020-26264

This section provides more technical insights into the vulnerability.

Vulnerability Description

The vulnerability in Go Ethereum (Geth) before version 1.9.25 allows a denial-of-service attack via a malicious GetProofsV2 request from a connected LES client.

Affected Systems and Versions

Product: go-ethereum
Vendor: ethereum
Versions Affected: < 1.9.25

Exploitation Mechanism

The vulnerability can be exploited by sending a malicious GetProofsV2 request from a connected LES client to crash the LES server.

Mitigation and Prevention

To address and prevent the exploitation of CVE-2020-26264, follow these steps:

Immediate Steps to Take

Update Go Ethereum to version 1.9.25 or newer to apply the patch.
If not required, disable the LES server to mitigate the vulnerability.

Long-Term Security Practices

Regularly update software and apply security patches promptly.
Implement network security measures to detect and prevent denial-of-service attacks.

Patching and Updates

Ensure timely patching of software and keep abreast of security advisories to protect against known vulnerabilities.