CVE-2023-28431 Explained : Impact and Mitigation

An overview of the CVE-2023-28431 vulnerability affecting Frontier's

modexp

precompile in version <= 0.1.0.

Understanding CVE-2023-28431

Exploring the details of the vulnerability and its impact on systems running Frontier's

modexp

precompile.

What is CVE-2023-28431?

CVE-2023-28431 is a vulnerability in Frontier's

modexp

precompile, utilized in the Ethereum compatibility layer for Substrate. The issue arises from the implementation of the

num-bigint

crate, where a discrepancy in gas costs between even and odd modulus calculations can lead to denial of service attacks.

The Impact of CVE-2023-28431

The vulnerability allows attackers to potentially disrupt service availability by exploiting the gas cost discrepancy in the

modexp

precompile, affecting systems running Frontier version <= 0.1.0.

Technical Details of CVE-2023-28431

Delving into the technical aspects of the CVE-2023-28431 vulnerability.

Vulnerability Description

Frontier's

modexp

precompile treats even and odd modulus calculations differently, leading to a gas cost inconsistency that could be exploited for denial of service attacks.

Affected Systems and Versions

The vulnerability affects systems using Frontier's

modexp

precompile in version <= 0.1.0.

Exploitation Mechanism

Attackers can exploit the gas cost inconsistency in the

modexp

precompile to launch denial of service attacks on vulnerable systems.

Mitigation and Prevention

Understanding how to mitigate the risks associated with CVE-2023-28431 and prevent potential exploits.

Immediate Steps to Take

Implement the short-term fix deployed in pull request 1017, which raises gas costs for even moduli in Frontier's

modexp

precompile.

Long-Term Security Practices

Ensure timely updates and patches from Frontier and

num-bigint

to address the underlying vulnerability in the long term.

Patching and Updates

Stay informed about upcoming fixes and developments related to CVE-2023-28431, and apply relevant patches and updates to secure systems running Frontier's

modexp

precompile.