CVE-2022-36083: Medium Vulnerability in jose_project jose

CVE-2022-36083 is a medium-severity vulnerability affecting the jose library, which is used for JSON Web Encryption (JWE). This vulnerability allows an adversary to exploit the PBKDF2 key management algorithms by setting an excessively high PBES2 Count value, leading to potential resource exhaustion. This scenario is particularly concerning when dealing with untrusted sources, which could result in significant CPU consumption.

The CVSS score for this vulnerability is 5.3, indicating a medium severity level. Risk to organizations includes potential denial of service due to excessive CPU usage, impacting system performance and availability. Organizations should prioritize addressing this issue as it affects users utilizing JWE decryption APIs with symmetric secrets from untrusted parties.

It is crucial for organizations to assess their current implementations of the jose library. The vulnerability was published on September 7, 2022, and has been modified since its initial disclosure. Organizations are urged to upgrade to versions that limit the PBKDF2 iteration count to 10,000 by default, such as v1.28.2, v2.0.6, v3.20.4, and v4.9.2. Immediate action is required to mitigate risks associated with this flaw.

No public exploit has been confirmed for this vulnerability, and it is not listed in the Known Exploited Vulnerabilities (KEV) database. However, its existence represents a potential threat, warranting attention from security teams.

Organizations should ensure that their environments are not vulnerable to excessive CPU usage by validating the implementation of the jose library. Additionally, they should be ready to apply patches or workarounds to mitigate this risk.

Vulnerability Details

The official description of this vulnerability indicates that the PBKDF2-based JWE key management algorithms expect a JOSE header parameter named `p2c`, which determines how many iterations of PBKDF2 must be executed. This design choice aims to slow down brute-force and dictionary attacks, enhancing security. However, when processing JWE from untrusted sources, an attacker can manipulate this parameter to force the environment to consume excessive CPU resources.

The CVSS vector indicates a network attack vector with low complexity, requiring no privileges or user interaction. The impact on availability is rated as low, but the potential for resource exhaustion poses a significant risk to the affected systems.

Technical Analysis

The root cause of this vulnerability lies in the handling of the PBKDF2 iteration count within the decryption process of JWE. When the `p2c` parameter is set to a very high value, it can cause the decryption operation to consume excessive CPU resources. This situation is aggravated in environments where the JWE is accepted without proper validation of the header parameters.

The attack vector is primarily network-based, as the vulnerability can be exploited through crafted JWE messages sent to a vulnerable service. The attack complexity is low since it does not require significant technical skill to manipulate the `p2c` parameter. No privileges are required to exploit this vulnerability, and user interaction is not necessary.

The potential impact on availability is classified as low, but under specific circumstances, it could significantly affect the responsiveness of the application processing the JWE.

Risk & Impact Analysis

The real-world deployment risk for organizations using the jose library is considerable, especially for those who accept JWE from untrusted sources without adequate validation. The vulnerability allows an attacker to exhaust system resources, potentially leading to denial of service. This can affect not only the targeted application but also impact overall system performance.

Given the CVSS score of 5.3, organizations should address this vulnerability in their priority patch cycle. Ensuring that the jose library is updated to a secure version limits the maximum PBKDF2 iteration count, thus reducing the risk of resource exhaustion.

Exploitation Status

Affected Versions

The vulnerable versions of the jose library are as follows: All versions prior to v1.28.2, v2.0.6, v3.20.4, and v4.9.2. Users are encouraged to upgrade to these versions or later to mitigate the vulnerability.

Mitigation & Remediation

Organizations should prioritize patching the jose library to the latest version, specifically v4.9.2, which limits the maximum PBKDF2 iteration count to 10,000 by default. If immediate upgrades are not feasible, users can utilize the `keyManagementAlgorithms` decryption option to disable PBKDF2 or inspect the JOSE Header before decryption to limit the `p2c` parameter.

For further guidance on secure coding practices, organizations may refer to our resources on secure coding practices to help mitigate similar vulnerabilities in the future.

Detection Guidance

Organizations should monitor logs for anomalies indicating excessive resource consumption, particularly during JWE decryption operations. Implementing alert mechanisms for unusual CPU usage patterns can provide early warning signs of potential exploitation.

AppSecure Threat Intelligence Insight

The long-term significance of CVE-2022-36083 highlights the critical need for libraries to enforce safe usage patterns, especially when handling cryptographic operations. The vulnerability underscores the importance of validating inputs from untrusted sources.

Security teams should take this incident as a lesson to improve their security posture by implementing stricter validation mechanisms and monitoring for unusual patterns.

For more insights on security best practices and vulnerability management, organizations can explore our articles on penetration testing methodology and vulnerability management programs.

As organizations navigate the complexities of application security, understanding vulnerabilities like CVE-2022-36083 will aid in developing a robust security strategy.