# Comparison Using Wrong Factors (CWE-1024)

The code performs a comparison between two entities, but the comparison is done using the wrong factors or criteria.

- Prevalence: Medium 1 language covered
- Impact: Medium Review recommended
- Prevention: Documented 1 fix examples

**OWASP:** Injection (A03:2021-Injection) - #3

## Description

When comparisons use incorrect criteria, security checks may not work as intended. For example, comparing objects by reference instead of by value, or using case-sensitive comparison when case-insensitive is required.

## Prevention

Prevention strategies for Comparison of Incompatible Types based on 1 Shoulder detection rules.

### Node.js

Use strict equality (===) and explicit type checking for security comparisons

## Warning Signs

- [MEDIUM] Loose equality operator ... used in security-critical context: ...
- [MEDIUM] unsafe use of loose equality operators (==, !=) and type coercion patterns
that can lead to security

## Consequences

- Bypass Protection Mechanism
- Gain Privileges

## Mitigations

- Carefully review comparison logic in security-sensitive code
- Use appropriate comparison methods for the data type
- Test comparison logic with edge cases

## Detection

- Total rules: 1
- Languages: javascript, typescript

## Rules by Language

### Javascript (1 rules)

- **Type Coercion Security Bugs** [MEDIUM]: Detects unsafe use of loose equality operators (==, !=) and type coercion patterns
that can lead to security vulnerabilities. JavaScript's type coercion can cause
unexpected behavior in security-critical code.

Common security issues from type coercion:
1. Authentication bypass: password == null matches both null AND undefined
2. Authorization bypass: role == "admin" can be bypassed with role = true
3. Input validation bypass: value == 0 matches "", [], false, "0"
4. SQL/NoSQL injection: params == {} doesn't check for actual object properties

Type coercion rules in JavaScript:
- null == undefined (true)
- 0 == "" == false == [] (all true)
- "0" == 0 (true)
- " \t\n" == 0 (true)
- But: "0" != false (because string vs boolean)

Security implications are severe when used in:
- Authentication/authorization checks
- Input validation
- Null/undefined checks
- Role/permission comparisons
  - Remediation: Use strict equality (===, !==) to avoid type coercion bugs.

### Typescript (1 rules)

- **Type Coercion Security Bugs** [MEDIUM]: Detects unsafe use of loose equality operators (==, !=) and type coercion patterns
that can lead to security vulnerabilities. JavaScript's type coercion can cause
unexpected behavior in security-critical code.

Common security issues from type coercion:
1. Authentication bypass: password == null matches both null AND undefined
2. Authorization bypass: role == "admin" can be bypassed with role = true
3. Input validation bypass: value == 0 matches "", [], false, "0"
4. SQL/NoSQL injection: params == {} doesn't check for actual object properties

Type coercion rules in JavaScript:
- null == undefined (true)
- 0 == "" == false == [] (all true)
- "0" == 0 (true)
- " \t\n" == 0 (true)
- But: "0" != false (because string vs boolean)

Security implications are severe when used in:
- Authentication/authorization checks
- Input validation
- Null/undefined checks
- Role/permission comparisons
  - Remediation: Use strict equality (===, !==) to avoid type coercion bugs.