CVE-2023-23940 : What You Need to Know

This CVE-2023-23940 involves a vulnerability in OpenZeppelin Contracts for Cairo that allows for signature validation bypass, potentially leading to malicious attacks. The vulnerability was discovered and published by GitHub_M on February 3, 2023.

Understanding CVE-2023-23940

OpenZeppelin Contracts for Cairo is a library used for secure smart contract development in Cairo for StarkNet, a decentralized ZK Rollup. The vulnerability arises from the lack of calling

finalize_keccak

after

verify_eth_signature

in the

is_valid_eth_signature

function. This flaw allows a malicious sequencer to bypass signature validation and impersonate instances of affected accounts.

What is CVE-2023-23940?

The CVE-2023-23940 vulnerability in OpenZeppelin Contracts for Cairo enables attackers to exploit the signature validation process, potentially leading to unauthorized access or impersonation of specific accounts.

The Impact of CVE-2023-23940

The impact of CVE-2023-23940 is significant, as it could allow malicious actors to impersonate legitimate accounts, leading to potential financial losses, reputation damage, or unauthorized access to sensitive data stored in affected smart contracts.

Technical Details of CVE-2023-23940

The vulnerability (CVE-2023-23940) stems from the improper verification of cryptographic signatures in the

is_valid_eth_signature

function within the OpenZeppelin Cairo Contracts library. The affected versions range from

0.2.0

to

< 0.6.1

.

Vulnerability Description

The vulnerability arises due to the absence of a call to

finalize_keccak

post

verify_eth_signature

, allowing malicious sequencers to exploit the signature validation process and impersonate affected accounts.

Affected Systems and Versions

The vulnerability impacts OpenZeppelin's Cairo Contracts library versions

>= 0.2.0

and

< 0.6.1

, leaving systems within this range susceptible to the signature validation bypass issue.

Exploitation Mechanism

Attackers can exploit the CVE-2023-23940 vulnerability by leveraging the missing call to

finalize_keccak

after

verify_eth_signature

, enabling them to circumvent signature validation checks and potentially conduct unauthorized activities within affected accounts.

Mitigation and Prevention

Addressing the CVE-2023-23940 vulnerability requires immediate actions to mitigate risks and prevent potential attacks on systems utilizing the vulnerable OpenZeppelin Cairo Contracts library.

Immediate Steps to Take

Users are advised to update to the patched version

0.6.1

or higher to remediate the signature validation bypass vulnerability and enhance security measures within their smart contracts.

Long-Term Security Practices

Incorporating robust security practices, such as thorough code reviews, cryptographic best practices, and regular vulnerability assessments, can help prevent similar vulnerabilities and enhance the overall security posture of smart contracts.

Patching and Updates

Regularly monitoring security advisories and promptly applying patches and updates released by OpenZeppelin can help organizations stay protected against emerging vulnerabilities and ensure the integrity of their smart contract deployments.