EUVD-2024-2974

Comprehensive Technical Analysis of EUVD-2024-2974

1. Vulnerability Assessment and Severity Evaluation

The vulnerability EUVD-2024-2974, also known as CVE-2023-25581, affects the pac4j-core library prior to version 4.0.0. This vulnerability is classified as a Java deserialization issue, which can lead to Remote Code Execution (RCE). The severity of this vulnerability is rated with a CVSS base score of 9.2, indicating a critical risk. The CVSS vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N highlights the following characteristics:

• Attack Vector (AV): Network (N) - The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) - The attack requires minimal complexity to execute.
• Authentication (AT): Physical (P) - The attacker needs physical access to the system.
• Privileges Required (PR): None (N) - No special privileges are required to exploit the vulnerability.
• User Interaction (UI): None (N) - No user interaction is required for the attack to succeed.
• Confidentiality (VC): High (H) - The vulnerability can lead to a high impact on confidentiality.
• Integrity (VI): High (H) - The vulnerability can lead to a high impact on integrity.
• Availability (VA): High (H) - The vulnerability can lead to a high impact on availability.

2. Potential Attack Vectors and Exploitation Methods

The primary attack vector involves providing an attribute that contains a serialized Java object with a special prefix {#sb64} and Base64 encoding. This can be achieved through:

• Network-Based Attacks: An attacker can send crafted serialized objects over the network to a vulnerable system.
• Man-in-the-Middle (MitM) Attacks: Intercepting and modifying network traffic to inject malicious serialized objects.
• Physical Access: Directly accessing the system to inject malicious serialized objects into the UserProfile class attributes.

Exploitation methods may include:

• Gadget Chains: Utilizing existing Java classes and methods (gadgets) to perform malicious actions during deserialization.
• Custom Payloads: Crafting custom serialized objects that exploit the vulnerability to execute arbitrary code.

3. Affected Systems and Software Versions

The vulnerability affects systems using the pac4j-core library versions prior to 4.0.0. Specifically:

• pac4j-core < 4.0.0: Any system or application that uses this version of the library is at risk.

4. Recommended Mitigation Strategies

To mitigate this vulnerability, the following actions are recommended:

• Upgrade to Version 4.0.0 or Later: Upgrade the pac4j-core library to version 4.0.0 or later, which addresses the deserialization issue.
• Input Validation: Implement strict input validation to ensure that only expected and safe data is processed.
• Deserialization Controls: Use secure deserialization practices, such as whitelisting allowed classes and using RestrictedObjectInputStream effectively.
• Network Security: Implement robust network security measures, including firewalls, intrusion detection systems (IDS), and encryption to protect against network-based attacks.
• Regular Audits: Conduct regular security audits and code reviews to identify and mitigate potential vulnerabilities.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to the European cybersecurity landscape, particularly for organizations that rely on Java-based security frameworks like pac4j. The potential for RCE can lead to severe consequences, including data breaches, unauthorized access, and system compromises. Given the critical nature of the vulnerability, it is essential for European organizations to prioritize patching and implementing robust security measures to protect against such threats.

6. Technical Details for Security Professionals

For security professionals, the following technical details are pertinent:

• Vulnerable Class: The vulnerability resides in the UserProfile class of the pac4j-core library.
• Serialization Prefix: The special prefix {#sb64} followed by Base64 encoding is used to exploit the vulnerability.
• RestrictedObjectInputStream: Although a RestrictedObjectInputStream is in place, it allows a broad range of Java packages, making it potentially exploitable with different gadget chains.
• References:
  • NVD CVE-2023-25581
  • ysoserial GitHub
  • pac4j GitHub
  • InternalAttributeHandler Source Code
  • PortSwigger Deserialization
  • GitHub Security Lab Advisories
  • GHSL-2022-085_pac4j

By understanding these details, security professionals can better assess the risk and implement effective mitigation strategies to protect their systems.