Overview

The linqi application has been found to contain hardcoded cryptographic keys and uses a weak algorithm with a limited ASCII charset to dynamically generate Initialization Vectors (IVs) for AES/CBC encryption. This makes known-plaintext attacks feasible, allowing an attacker with local access to decrypt sensitive obfuscated strings, including ConnectionString values containing database credentials from appsettings.json.

Technical Details

The vulnerabilities in the linqi application are twofold:

  1. Hardcoded Cryptographic Keys: The application contains hardcoded cryptographic keys. This is a significant security risk because if an attacker gains access to these keys, they can decrypt sensitive data.
  2. Weak IV Generation: The application uses a weak algorithm with a limited ASCII charset to dynamically generate IVs for AES/CBC encryption. This weakness makes it feasible for attackers to perform known-plaintext attacks.

An attacker with local access can leverage these vulnerabilities to decrypt sensitive obfuscated strings. Specifically, they can access ConnectionString values containing database credentials from appsettings.json. This could lead to unauthorized access to sensitive data and potentially allow for further exploitation of the system.

Impact Analysis

The impact of this vulnerability is significant. With a CVSS v4.0 base score of 8.5, the vulnerability is rated as HIGH severity. The attack vector is LOCAL, meaning an attacker needs to have local access to exploit the vulnerability. The attack complexity is LOW, and no user interaction is required. The confidentiality, integrity, and availability impacts are all HIGH.

Mitigation

To mitigate this vulnerability, the following steps should be taken:

  1. Rotate Hardcoded Keys: Immediately rotate any hardcoded cryptographic keys. This will prevent attackers from using these keys to decrypt sensitive data even if they gain access to them.
  2. Improve IV Generation: Update the IV generation algorithm to use a more secure method. This could involve using a larger charset or a more complex algorithm to ensure IVs are generated securely.
  3. Implement Secure Key Management: Implement a secure key management system to handle cryptographic keys securely. This includes secure generation, distribution, and storage of keys.
  4. Limit Access: Ensure that only necessary personnel have local access to the system. This will reduce the risk of an attacker gaining access to exploit the vulnerability.
  5. Regular Security Audits: Perform regular security audits to identify and address any similar vulnerabilities in the future.