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C#

C# static code analysis

Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C# code

  • All rules 493
  • Vulnerability46
  • Bug88
  • Security Hotspot24
  • Code Smell335

  • Quick Fix 61
 
Tags
    Impact
      Clean code attribute
        1. Using unsafe code blocks is security-sensitive

           Security Hotspot
        2. Not specifying a timeout for regular expressions is security-sensitive

           Security Hotspot
        3. Hard-coded secrets are security-sensitive

           Security Hotspot
        4. Constructing arguments of system commands from user input is security-sensitive

           Security Hotspot
        5. Deserializing objects without performing data validation is security-sensitive

           Security Hotspot
        6. Disabling ASP.NET "Request Validation" feature is security-sensitive

           Security Hotspot
        7. Allowing requests with excessive content length is security-sensitive

           Security Hotspot
        8. Using publicly writable directories is security-sensitive

           Security Hotspot
        9. Using clear-text protocols is security-sensitive

           Security Hotspot
        10. Having a permissive Cross-Origin Resource Sharing policy is security-sensitive

           Security Hotspot
        11. Expanding archive files without controlling resource consumption is security-sensitive

           Security Hotspot
        12. Configuring loggers is security-sensitive

           Security Hotspot
        13. Using weak hashing algorithms is security-sensitive

           Security Hotspot
        14. Delivering code in production with debug features activated is security-sensitive

           Security Hotspot
        15. Disabling CSRF protections is security-sensitive

           Security Hotspot
        16. Searching OS commands in PATH is security-sensitive

           Security Hotspot
        17. Creating cookies without the "HttpOnly" flag is security-sensitive

           Security Hotspot
        18. Setting loose file permissions is security-sensitive

           Security Hotspot
        19. Using non-standard cryptographic algorithms is security-sensitive

           Security Hotspot
        20. Using pseudorandom number generators (PRNGs) is security-sensitive

           Security Hotspot
        21. Creating cookies without the "secure" flag is security-sensitive

           Security Hotspot
        22. Formatting SQL queries is security-sensitive

           Security Hotspot
        23. Hard-coded credentials are security-sensitive

           Security Hotspot
        24. Using hardcoded IP addresses is security-sensitive

           Security Hotspot

        Using pseudorandom number generators (PRNGs) is security-sensitive

        responsibility - trustworthy
        security
        Security Hotspot
        • cwe

        PRNGs are algorithms that produce sequences of numbers that only approximate true randomness. While they are suitable for applications like simulations or modeling, they are not appropriate for security-sensitive contexts because their outputs can be predictable if the internal state is known.

        In contrast, cryptographically secure pseudorandom number generators (CSPRNGs) are designed to be secure against prediction attacks. CSPRNGs use cryptographic algorithms to ensure that the generated sequences are not only random but also unpredictable, even if part of the sequence or the internal state becomes known. This unpredictability is crucial for security-related tasks such as generating encryption keys, tokens, or any other values that must remain confidential and resistant to guessing attacks.

        For example, the use of non-cryptographic PRNGs has led to vulnerabilities such as:

        • CVE-2013-6386
        • CVE-2006-3419
        • CVE-2008-4102

        When software generates predictable values in a context requiring unpredictability, it may be possible for an attacker to guess the next value that will be generated, and use this guess to impersonate another user or access sensitive information. Therefore, it is critical to use CSPRNGs in any security-sensitive application to ensure the robustness and security of the system.

        As the System.Random class relies on a non-cryptographic pseudorandom number generator, it should not be used for security-critical applications or for protecting sensitive data. In such context, the System.Cryptography.RandomNumberGenerator class which relies on a CSPRNG should be used in place.

        Ask Yourself Whether

        • the code using the generated value requires it to be unpredictable. It is the case for all encryption mechanisms or when a secret value, such as a password, is hashed.
        • the function you use is a non-cryptographic PRNG.
        • the generated value is used multiple times.
        • an attacker can access the generated value.

        There is a risk if you answered yes to any of those questions.

        Recommended Secure Coding Practices

        • Only use random number generators which are recommended by OWASP or any other trusted organization.
        • Use the generated random values only once.
        • You should not expose the generated random value. If you have to store it, make sure that the database or file is secure.

        Sensitive Code Example

        var random = new Random(); // Sensitive use of Random
        byte[] data = new byte[16];
        random.NextBytes(data);
        return BitConverter.ToString(data); // Check if this value is used for hashing or encryption
        

        Compliant Solution

        using System.Security.Cryptography;
        ...
        var randomGenerator = RandomNumberGenerator.Create();
        byte[] data = new byte[16];
        randomGenerator.GetBytes(data);
        return BitConverter.ToString(data);
        

        See

        • OWASP - Secure Random Number Generation Cheat Sheet
        • OWASP - Top 10 2021 Category A2 - Cryptographic Failures
        • OWASP - Top 10 2017 Category A3 - Sensitive Data Exposure
        • CWE - CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
        • CWE - CWE-330 - Use of Insufficiently Random Values
        • CWE - CWE-326 - Inadequate Encryption Strength
        • CWE - CWE-1241 - Use of Predictable Algorithm in Random Number Generator
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          Available Since
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