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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
Filtered: 90 rules found
cwe
    Impact
      Clean code attribute
        1. Server-side requests should not be vulnerable to traversing attacks

           Vulnerability
        2. JWT secret keys should not be disclosed

           Vulnerability
        3. Loop boundaries should not be vulnerable to injection attacks

           Vulnerability
        4. Connection strings should not be vulnerable to injections attacks

           Vulnerability
        5. Memory allocations should not be vulnerable to Denial of Service attacks

           Vulnerability
        6. Accessing files should not lead to filesystem oracle attacks

           Vulnerability
        7. Environment variables should not be defined from untrusted input

           Vulnerability
        8. Blocks should not be synchronized on local variables

           Bug
        9. Not specifying a timeout for regular expressions is security-sensitive

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

           Security Hotspot
        11. XML operations should not be vulnerable to injection attacks

           Vulnerability
        12. Constructing arguments of system commands from user input is security-sensitive

           Security Hotspot
        13. Applications should not create session cookies from untrusted input

           Vulnerability
        14. Reflection should not be vulnerable to injection attacks

           Vulnerability
        15. Extracting archives should not lead to zip slip vulnerabilities

           Vulnerability
        16. OS commands should not be vulnerable to argument injection attacks

           Vulnerability
        17. Types allowed to be deserialized should be restricted

           Vulnerability
        18. Deserializing objects without performing data validation is security-sensitive

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

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

           Security Hotspot
        21. JWT should be signed and verified with strong cipher algorithms

           Vulnerability
        22. Cipher algorithms should be robust

           Vulnerability
        23. Encryption algorithms should be used with secure mode and padding scheme

           Vulnerability
        24. Insecure temporary file creation methods should not be used

           Vulnerability
        25. Using publicly writable directories is security-sensitive

           Security Hotspot
        26. Passwords should not be stored in plaintext or with a fast hashing algorithm

           Vulnerability
        27. Dynamic code execution should not be vulnerable to injection attacks

           Vulnerability
        28. Using clear-text protocols is security-sensitive

           Security Hotspot
        29. NoSQL operations should not be vulnerable to injection attacks

           Vulnerability
        30. HTTP request redirections should not be open to forging attacks

           Vulnerability
        31. Logging should not be vulnerable to injection attacks

           Vulnerability
        32. Server-side requests should not be vulnerable to forging attacks

           Vulnerability
        33. Deserialization should not be vulnerable to injection attacks

           Vulnerability
        34. Endpoints should not be vulnerable to reflected cross-site scripting (XSS) attacks

           Vulnerability
        35. Having a permissive Cross-Origin Resource Sharing policy is security-sensitive

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

           Security Hotspot
        37. Server certificates should be verified during SSL/TLS connections

           Vulnerability
        38. Using weak hashing algorithms is security-sensitive

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

           Security Hotspot
        40. Disabling CSRF protections is security-sensitive

           Security Hotspot
        41. Unread "private" fields should be removed

           Code Smell
        42. LDAP connections should be authenticated

           Vulnerability
        43. Cryptographic keys should be robust

           Vulnerability
        44. Weak SSL/TLS protocols should not be used

           Vulnerability
        45. Secure random number generators should not output predictable values

           Vulnerability
        46. Searching OS commands in PATH is security-sensitive

           Security Hotspot
        47. Empty nullable value should not be accessed

           Bug
        48. Database queries should not be vulnerable to injection attacks

           Vulnerability
        49. Creating cookies without the "HttpOnly" flag is security-sensitive

           Security Hotspot
        50. Cipher Block Chaining IVs should be unpredictable

           Vulnerability
        51. Classes should "Dispose" of members from the classes' own "Dispose" methods

           Bug
        52. Classes with "IDisposable" members should implement "IDisposable"

           Bug
        53. "IDisposables" should be disposed

           Bug
        54. XML parsers should not be vulnerable to XXE attacks

           Vulnerability
        55. Multiline blocks should be enclosed in curly braces

           Code Smell
        56. Regular expressions should not be vulnerable to Denial of Service attacks

           Vulnerability
        57. Setting loose file permissions is security-sensitive

           Security Hotspot
        58. Boolean expressions should not be gratuitous

           Code Smell
        59. Conditionally executed code should be reachable

           Bug
        60. Generic exceptions should not be ignored

           Code Smell
        61. Blocks should be synchronized on read-only fields

           Bug
        62. Mutable fields should not be "public static"

           Code Smell
        63. Null pointers should not be dereferenced

           Bug
        64. Using non-standard cryptographic algorithms is security-sensitive

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

           Security Hotspot
        66. "ToString()" method should not return null

           Bug
        67. Locks should be released on all paths

           Bug
        68. "Exception" should not be caught

           Code Smell
        69. Results of integer division should not be assigned to floating point variables

           Bug
        70. A secure password should be used when connecting to a database

           Vulnerability
        71. Creating cookies without the "secure" flag is security-sensitive

           Security Hotspot
        72. XPath expressions should not be vulnerable to injection attacks

           Vulnerability
        73. I/O function calls should not be vulnerable to path injection attacks

           Vulnerability
        74. LDAP queries should not be vulnerable to injection attacks

           Vulnerability
        75. Formatting SQL queries is security-sensitive

           Security Hotspot
        76. OS commands should not be vulnerable to command injection attacks

           Vulnerability
        77. Hard-coded credentials are security-sensitive

           Security Hotspot
        78. Password hashing functions should use an unpredictable salt

           Vulnerability
        79. Invalid casts should be avoided

           Code Smell
        80. Unused assignments should be removed

           Code Smell
        81. "==" should not be used when "Equals" is overridden

           Code Smell
        82. NullReferenceException should not be caught

           Code Smell
        83. "switch/Select" statements should contain a "default/Case Else" clauses

           Code Smell
        84. "Equals(Object)" and "GetHashCode()" should be overridden in pairs

           Bug
        85. Exit methods should not be called

           Code Smell
        86. Track uses of "TODO" tags

           Code Smell
        87. Track uses of "FIXME" tags

           Code Smell
        88. Assignments should not be made from within sub-expressions

           Code Smell
        89. General or reserved exceptions should never be thrown

           Code Smell
        90. Fields should not have public accessibility

           Code Smell

        Having a permissive Cross-Origin Resource Sharing policy is security-sensitive

        intentionality - complete
        security
        Security Hotspot
        • cwe

        Having a permissive Cross-Origin Resource Sharing policy is security-sensitive. It has led in the past to the following vulnerabilities:

        • CVE-2018-0269
        • CVE-2017-14460

        Same origin policy in browsers prevents, by default and for security-reasons, a javascript frontend to perform a cross-origin HTTP request to a resource that has a different origin (domain, protocol, or port) from its own. The requested target can append additional HTTP headers in response, called CORS, that act like directives for the browser and change the access control policy / relax the same origin policy.

        Ask Yourself Whether

        • You don’t trust the origin specified, example: Access-Control-Allow-Origin: untrustedwebsite.com.
        • Access control policy is entirely disabled: Access-Control-Allow-Origin: *
        • Your access control policy is dynamically defined by a user-controlled input like origin header.

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

        Recommended Secure Coding Practices

        • The Access-Control-Allow-Origin header should be set only for a trusted origin and for specific resources.
        • Allow only selected, trusted domains in the Access-Control-Allow-Origin header. Prefer whitelisting domains over blacklisting or allowing any domain (do not use * wildcard nor blindly return the Origin header content without any checks).

        Sensitive Code Example

        ASP.NET Core MVC:

        [HttpGet]
        public string Get()
        {
            Response.Headers.Add("Access-Control-Allow-Origin", "*"); // Sensitive
            Response.Headers.Add(HeaderNames.AccessControlAllowOrigin, "*"); // Sensitive
        }
        
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddCors(options =>
            {
                options.AddDefaultPolicy(builder =>
                {
                    builder.WithOrigins("*"); // Sensitive
                });
        
                options.AddPolicy(name: "EnableAllPolicy", builder =>
                {
                    builder.WithOrigins("*"); // Sensitive
                });
        
                options.AddPolicy(name: "OtherPolicy", builder =>
                {
                    builder.AllowAnyOrigin(); // Sensitive
                });
            });
        
            services.AddControllers();
        }
        

        ASP.NET MVC:

        public class HomeController : ApiController
        {
            public HttpResponseMessage Get()
            {
                var response = HttpContext.Current.Response;
        
                response.Headers.Add("Access-Control-Allow-Origin", "*"); // Sensitive
                response.Headers.Add(HeaderNames.AccessControlAllowOrigin, "*"); // Sensitive
                response.AppendHeader(HeaderNames.AccessControlAllowOrigin, "*"); // Sensitive
            }
        }
        
        [EnableCors(origins: "*", headers: "*", methods: "GET")] // Sensitive
        public HttpResponseMessage Get() => new HttpResponseMessage()
        {
            Content = new StringContent("content")
        };
        

        User-controlled origin:

        String origin = Request.Headers["Origin"];
        Response.Headers.Add("Access-Control-Allow-Origin", origin); // Sensitive
        

        Compliant Solution

        ASP.NET Core MVC:

        [HttpGet]
        public string Get()
        {
            Response.Headers.Add("Access-Control-Allow-Origin", "https://trustedwebsite.com"); // Safe
            Response.Headers.Add(HeaderNames.AccessControlAllowOrigin, "https://trustedwebsite.com"); // Safe
        }
        
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddCors(options =>
            {
                options.AddDefaultPolicy(builder =>
                {
                    builder.WithOrigins("https://trustedwebsite.com", "https://anothertrustedwebsite.com"); // Safe
                });
        
                options.AddPolicy(name: "EnableAllPolicy", builder =>
                {
                    builder.WithOrigins("https://trustedwebsite.com"); // Safe
                });
            });
        
            services.AddControllers();
        }
        

        ASP.Net MVC:

        public class HomeController : ApiController
        {
            public HttpResponseMessage Get()
            {
                var response = HttpContext.Current.Response;
        
                response.Headers.Add("Access-Control-Allow-Origin", "https://trustedwebsite.com");
                response.Headers.Add(HeaderNames.AccessControlAllowOrigin, "https://trustedwebsite.com");
                response.AppendHeader(HeaderNames.AccessControlAllowOrigin, "https://trustedwebsite.com");
            }
        }
        
        [EnableCors(origins: "https://trustedwebsite.com", headers: "*", methods: "GET")]
        public HttpResponseMessage Get() => new HttpResponseMessage()
        {
            Content = new StringContent("content")
        };
        

        User-controlled origin validated with an allow-list:

        String origin = Request.Headers["Origin"];
        
        if (trustedOrigins.Contains(origin))
        {
            Response.Headers.Add("Access-Control-Allow-Origin", origin);
        }
        

        See

        • OWASP - Top 10 2021 Category A5 - Security Misconfiguration
        • OWASP - Top 10 2021 Category A7 - Identification and Authentication Failures
        • developer.mozilla.org - CORS
        • developer.mozilla.org - Same origin policy
        • OWASP - Top 10 2017 Category A6 - Security Misconfiguration
        • OWASP HTML5 Security Cheat Sheet - Cross Origin Resource Sharing
        • CWE - CWE-346 - Origin Validation Error
        • CWE - CWE-942 - Overly Permissive Cross-domain Whitelist
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