When a Simple C# Enum Becomes a Security Risk
A C # Enum often looks harmless, but it can easily create privilege flaws if values overlap or validation is missing.
Many developers rely on C # Enum Enum or flag enums for permission control, but if you don’t enforce unique, validated values, logic breaks silently. Insecure example, for educational purposes only.
⚠️Insecure example, for educational purposes only. Do not use in production.
public enum UserRole
{
None = 0,
User = 1,
Admin = 2,
SuperAdmin = 3 // ❌ Overlaps with Admin
}
Secure version:
public enum UserRole
{
None = 0,
User = 1,
Admin = 2,
SuperAdmin = 4
}
// # Educational note: Always assign unique power-of-two values for flag enums.
Educational note: Even a simple C sharp enum like this can expose critical endpoints if unchecked values pass validation layers.
Common Vulnerabilities in Flag Enums and C# Enum Logic
Most security issues come from flag enums or unsafe casting of C # enum data.
Invalid Casting
⚠️Insecure example, for educational purposes only:
var role = (UserRole)Enum.Parse(typeof(UserRole), input);
Attackers can send undefined integers to trigger unexpected logic paths.
Secure version:
if (!Enum.TryParse(input, out UserRole role) || !Enum.IsDefined(typeof(UserRole), role))
throw new InvalidOperationException("Invalid role value");
Educational note: Always validate parsed values for C # enum and flag enums.
Flag C# Enums Gone Wrong
⚠️Insecure example, for educational purposes only:
[Flags]
public enum Permissions
{
None = 0,
Read = 1,
Write = 2,
Admin = 3 // ❌ Overlaps with Read + Write
}
Secure version:
[Flags]
public enum Permissions
{
None = 0,
Read = 1,
Write = 2,
Delete = 4,
Admin = 8
}
Educational note: Define flag enums using distinct powers of two.
Incorrectly defined flag enums are one of the easiest ways to cause privilege escalation in C # enum logic.
Serialization Pitfalls in C Sharp Enum Handling
Loose serialization of C sharp enum values can expose your app to inconsistent states or deserialization attacks.
⚠️Insecure example, for educational purposes only:
var data = JsonSerializer.Deserialize<User>(payload);
If payload contains "Role": 99, it maps to an invalid c# enum enum value.
Secure version:
var opts = new JsonSerializerOptions
{
Converters = { new JsonStringEnumConverter(JsonNamingPolicy.CamelCase, allowIntegerValues: false) }
};
var data = JsonSerializer.Deserialize<User>(payload, opts);
Educational note: Never allow numeric enum deserialization from untrusted input.
Preventing C# Enum Logic Errors in DevSecOps Pipelines
DevSecOps teams should automate validation for every C # Enum, C sharp enum, and flag enum definition to prevent inconsistent states.
Example, secure pipeline integration:
- name: Validate enum definitions
run: |
dotnet test --filter Category=EnumValidation
xygeni validate --rules enums
# Never expose real tokens or internal URLs in pipelines
Educational note: Static analysis can detect overlapping flag enums, unsafe deserialization, and missing switch cases, all before deployment.
Detecting Enum and Flag Issues With Xygeni
Xygeni Code Security automatically detects overlapping or inconsistent flag enum values, unsafe enum parsing, and missing validation in C# authorization logic.
- Overlapping or misaligned flag enum values
- Unsafe C# enum parsing logic
- Deserialization flaws in C# enum usage
- Missing validation or default cases in authorization logic
Example:
xygeni scan --detect enumsEducational note: Use Xygeni to enforce enum integrity and secure flag enums.
Xygeni validates enum definitions, detects overlapping or inconsistent values, and applies automatic enforcement in CI/CD pipelines through:
xygeni validate --rules enums
Strong Logic Requires Strong Typing and Validation
Whether using standard C# enums or complex flag enums, every value must be explicit, validated, and tested. Unchecked integers or overlapping flags can lead to privilege escalation, unsafe state changes, and logical inconsistencies. With Xygeni, teams automate the detection and validation of enum definitions, ensuring strong typing, predictable logic, and secure behavior from development to deployment.
