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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 315
  • Vulnerability13
  • Bug76
  • Security Hotspot19
  • Code Smell207

  • Quick Fix 19
 
Tags
    Impact
      Clean code attribute
        1. Hard-coded secrets are security-sensitive

           Security Hotspot
        2. "sprintf" should not be used

           Security Hotspot
        3. Changing working directories without verifying the success is security-sensitive

           Security Hotspot
        4. Setting capabilities is security-sensitive

           Security Hotspot
        5. Using "tmpnam", "tmpnam_s" or "tmpnam_r" is security-sensitive

           Security Hotspot
        6. Using "strncpy" or "wcsncpy" is security-sensitive

           Security Hotspot
        7. Using "strncat" or "wcsncat" is security-sensitive

           Security Hotspot
        8. Using "strcat" or "wcscat" is security-sensitive

           Security Hotspot
        9. Using "strlen" or "wcslen" is security-sensitive

           Security Hotspot
        10. Changing directories improperly when using "chroot" is security-sensitive

           Security Hotspot
        11. Using "strcpy" or "wcscpy" is security-sensitive

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

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

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

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

           Security Hotspot
        16. Setting loose POSIX file permissions is security-sensitive

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

           Security Hotspot
        18. Hard-coded passwords are security-sensitive

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

           Security Hotspot

        Using pseudorandom number generators (PRNGs) is security-sensitive

        responsibility - trustworthy
        security
        Security Hotspot
        • cwe
        • cert

        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.

        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

        • Use functions which rely on a cryptographically secure pseudorandom number generator (CSPRNG) such as randombytes_uniform() or randombytes_buf() from libsodium, or randomize() from Botan.
        • 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

        #include <random>
        // ...
        
        void f() {
          int random_int = std::rand(); // Sensitive
        }
        

        Compliant Solution

        #include <sodium.h>
        #include <botan/system_rng.h>
        // ...
        
        void f() {
          char random_chars[10];
          randombytes_buf(random_chars, 10);
          uint32_t random_int = randombytes_uniform(10);
        
          uint8_t random_chars[10];
          Botan::System_RNG system;
          system.randomize(random_chars, 10);
        }
        

        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
        • CERT, MSC30-C. - Do not use the rand() function for generating pseudorandom numbers
        • CERT, MSC50-CPP. - Do not use std::rand() for generating pseudorandom numbers
        • Derived from FindSecBugs rule Predictable Pseudo Random Number Generator
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