CVE-2021-41272 : Vulnerability Insights and Analysis

Besu is an Ethereum client written in Java. The vulnerability in SHL, SHR, and SAR operations could lead to execution failures and potential network forks.

Understanding CVE-2021-41272

This CVE details a vulnerability in Besu related to changes in the implementation of specific operations.

What is CVE-2021-41272?

Besu's version 21.10.0 introduced a signed type coercion error, impacting shifts between 2-4 billion bits in 32-bit signed integers. This issue could lead to transaction failures and forks in mining networks.

The Impact of CVE-2021-41272

The vulnerability has a CVSS base score of 7.5 (High severity) with a HIGH impact on availability, potentially causing forks in mining networks and hindering block validation.

Technical Details of CVE-2021-41272

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The issue arises from improper handling of specific numerical operations, resulting in a signed type coercion error that affects the execution and validation of smart contracts.

Affected Systems and Versions

Product: Besu
Vendor: Hyperledger
Versions: > 21.7.4, < 21.10.2

Exploitation Mechanism

The vulnerability can be exploited by crafting transactions with specific shift operations, impacting the execution and validation processes in Besu.

Mitigation and Prevention

To address CVE-2021-41272, the following steps can be taken:

Immediate Steps to Take

Upgrade to Besu version 21.10.2 containing the patch
Roll back to version 21.7.4 if unable to upgrade
Ensure all nodes run on non-vulnerable versions once a transaction with relevant operations is in the chain

Long-Term Security Practices

Regularly update Besu to the latest secure versions
Monitor security advisories from Hyperledger

Patching and Updates

Apply patches promptly
Follow best practices for secure smart contract development