CVE-2023-34459 : Exploit Details and Defense Strategies
Learn about CVE-2023-34459 affecting OpenZeppelin Contracts versions >= 4.7.0 and < 4.9.2. Find out the impact, vulnerability description, affected systems, exploitation mechanism, and mitigation steps.
OpenZeppelin Contracts is a library for smart contract development. A vulnerability in versions >= 4.7.0 and < 4.9.2 allows the forging of a valid multiproof for an arbitrary set of leaves by constructing merkle trees with a node value of 0 at depth 1.
Understanding CVE-2023-34459
This vulnerability in OpenZeppelin Contracts' MerkleProof multiproofs can allow proving arbitrary leaves for specific trees.
What is CVE-2023-34459?
CVE-2023-34459 is a medium severity vulnerability that arises due to improper validation of integrity check value in OpenZeppelin Contracts, enabling the forging of a valid multiproof for an arbitrary set of leaves.
The Impact of CVE-2023-34459
The impact of this vulnerability is considered medium, with a base CVSS score of 5.3. It can lead to a compromise of data integrity in affected systems.
Technical Details of CVE-2023-34459
The vulnerability description, affected systems, and exploitation mechanism in detail:
Vulnerability Description
When certain functions are in use, it is possible to construct merkle trees allowing malicious forging of a valid multiproof for specific leaves.
Affected Systems and Versions
The vulnerability affects OpenZeppelin Contracts versions >= 4.7.0 and < 4.9.2.
Exploitation Mechanism
By manipulating merkle trees with a node value of 0 at depth 1, attackers can forge a valid multiproof for arbitrary leaves.
Mitigation and Prevention
Effective steps for immediate mitigation and long-term security practices:
Immediate Steps to Take
- Upgrade to version 4.9.2 of OpenZeppelin Contracts to patch the vulnerability.
- When constructing merkle trees, hash the leaves and avoid inserting empty nodes.
Long-Term Security Practices
- Utilize the @openzeppelin/merkle-tree package for safe merkle tree operations.
- Avoid accepting user-provided merkle roots without reconstructing the tree's structure.
Patching and Updates
Ensure regular patching of software systems to stay protected against known vulnerabilities.