CVE-2017-12972 : Vulnerability Insights and Analysis

Nimbus JOSE+JWT prior to version 4.39 is affected by a vulnerability allowing potential attackers to exploit HMAC bypass attacks. This CVE was published on August 20, 2017.

Understanding CVE-2017-12972

This CVE identifies a lack of validation for integer-overflow when converting length values from bytes to bits in Nimbus JOSE+JWT.

What is CVE-2017-12972?

In Nimbus JOSE+JWT before version 4.39, a vulnerability exists due to the absence of an integer-overflow check when converting length values from bytes to bits. This flaw enables attackers to conduct HMAC bypass attacks.

The Impact of CVE-2017-12972

The vulnerability allows potential attackers to exploit HMAC bypass attacks by manipulating Additional Authenticated Data (AAD) and ciphertext, resulting in the retrieval of different plaintext values using the same HMAC.

Technical Details of CVE-2017-12972

Nimbus JOSE+JWT vulnerability details.

Vulnerability Description

The lack of validation for integer-overflow when converting length values from bytes to bits allows for HMAC bypass attacks through manipulation of AAD and ciphertext.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: Not applicable

Exploitation Mechanism

Attackers can exploit the vulnerability by utilizing shifting techniques on AAD and ciphertext to retrieve different plaintext values using the same HMAC.

Mitigation and Prevention

Protecting systems from CVE-2017-12972.

Immediate Steps to Take

Update Nimbus JOSE+JWT to version 4.39 or newer to mitigate the vulnerability.
Monitor for any unauthorized access or unusual activities on the system.

Long-Term Security Practices

Implement secure coding practices to prevent similar vulnerabilities in the future.
Regularly educate and train developers and security teams on best practices for secure coding.

Patching and Updates

Stay informed about security updates and patches released by Nimbus JOSE+JWT.
Promptly apply patches to ensure the system is protected against known vulnerabilities.