CVE-2021-29443 : Security Advisory and Response

A padding oracle attack due to an observable timing discrepancy has been discovered in the jose npm library. This vulnerability could allow an adversary to decrypt data without the decryption key in certain versions of the library.

Understanding CVE-2021-29443

This section provides insights into the nature and impact of the vulnerability.

What is CVE-2021-29443?

The jose npm library, which offers cryptographic operations, is susceptible to a padding oracle attack due to an observable timing discrepancy. Specifically, in vulnerable versions, decryption of AES_CBC_HMAC_SHA2 Algorithm may lead to a padding oracle scenario.

The Impact of CVE-2021-29443

The vulnerability could enable an attacker to exploit the observable timing difference during decryption and potentially decrypt sensitive data without needing the decryption key. This poses a significant risk to the confidentiality of the encrypted information.

Technical Details of CVE-2021-29443

This section delves into the technical aspects of the CVE, including the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

In affected versions of the jose library, a timing discrepancy during decryption can be leveraged by an adversary to conduct a padding oracle attack, compromising data confidentiality.

Affected Systems and Versions

The vulnerability impacts versions of the jose library prior to

1.28.1

,

2.0.5

, and

3.11.4

. Users of these versions are advised to upgrade to the respective fixed versions.

Exploitation Mechanism

Attackers could exploit the timing difference in padding errors during decryption to execute a padding oracle attack, potentially decrypting encrypted data without knowledge of the decryption key.

Mitigation and Prevention

In this section, we outline the necessary steps to mitigate the risks associated with CVE-2021-29443 and prevent potential exploitation.

Immediate Steps to Take

Users should promptly update their jose library to patched versions. For v1.x, upgrade to

^1.28.1

, for v2.x to

^2.0.5

, and for v3.x to

^3.11.4

to safeguard against the vulnerability.

Long-Term Security Practices

Implementing secure coding practices, regular security audits, and staying informed about library updates can help enhance the overall security posture.

Patching and Updates

Stay vigilant for security advisories related to the jose library and promptly apply patches and updates to mitigate emerging vulnerabilities.