CVE-2021-43839 : Exploit Details and Defense Strategies

Cronos is a commercial implementation of a blockchain. In Cronos nodes running versions before v0.6.5, a vulnerability allows taking transaction fees from Cosmos SDK's FeeCollector by sending a custom crafted MsgEthereumTx. All validator node operators are advised to upgrade to Cronos v0.6.5.

Understanding CVE-2021-43839

In this section, you will understand the impact and technical details of CVE-2021-43839.

What is CVE-2021-43839?

The vulnerability in Cronos before v0.6.5 allows unauthorized access to transaction fees from FeeCollector using a specific transaction.

The Impact of CVE-2021-43839

This vulnerability has a severity score of 7.5 (High). It can lead to potential financial losses and compromise the integrity of blockchain operations.

Technical Details of CVE-2021-43839

Let's delve into the technical aspects of CVE-2021-43839.

Vulnerability Description

The issue in Cronos versions prior to v0.6.5 enables attackers to exploit the FeeCollector to capture transaction fees.

Affected Systems and Versions

Product: Cronos
Vendor: crypto-org-chain
Vulnerable Version: < 0.6.5

Exploitation Mechanism

The vulnerability can be exploited by sending a specially crafted transaction (MsgEthereumTx) to gain access to transaction fees.

Mitigation and Prevention

Discover how to address and prevent the exploitation of CVE-2021-43839.

Immediate Steps to Take

Upgrade all Cronos nodes to version 0.6.5 to mitigate the vulnerability effectively.

Long-Term Security Practices

Regularly update and monitor blockchain implementations for security patches.
Conduct security audits to identify and address potential vulnerabilities.

Patching and Updates

Always stay up-to-date with vendor patches and security advisories to protect against known vulnerabilities.