CWE-480 Base Rascunho Low likelihood

Use of Incorrect Operator

This vulnerability occurs when a developer mistakenly uses the wrong operator in their code, leading to unintended and potentially insecure logic.

Definição

What is CWE-480?

This vulnerability occurs when a developer mistakenly uses the wrong operator in their code, leading to unintended and potentially insecure logic.
This flaw is almost always a simple typographical error, like using a single equals sign (=) for comparison instead of a double (== or ===), or confusing logical AND (&&) with OR (||). These small mistakes can drastically change how a program behaves, bypassing critical security checks, granting unintended access, or corrupting data. To prevent this, developers should adopt defensive coding practices like using linters and static analysis tools that can catch these errors automatically. Code reviews are also essential for spotting incorrect operators, especially in security-critical sections like authentication, authorization, and input validation routines.
Impacto no mundo real

Real-world CVEs caused by CWE-480

  • CVE-2022-3979

    Chain: data visualization program written in PHP uses the "!=" operator instead of the type-strict "!==" operator (CWE-480) when validating hash values, potentially leading to an incorrect type conversion (CWE-704)

  • CVE-2021-3116

    Chain: Python-based HTTP Proxy server uses the wrong boolean operators (CWE-480) causing an incorrect comparison (CWE-697) that identifies an authN failure if all three conditions are met instead of only one, allowing bypass of the proxy authentication (CWE-1390)

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    The following C/C++ and C# examples attempt to validate an int input parameter against the integer value 100.

  2. 2

    However, the expression to be evaluated in the if statement uses the assignment operator "=" rather than the comparison operator "==". The result of using the assignment operator instead of the comparison operator causes the int variable to be reassigned locally and the expression in the if statement will always evaluate to the value on the right hand side of the expression. This will result in the input value not being properly validated, which can cause unexpected results.

  3. 3

    The following C/C++ example shows a simple implementation of a stack that includes methods for adding and removing integer values from the stack. The example uses pointers to add and remove integer values to the stack array variable.

  4. 4

    The push method includes an expression to assign the integer value to the location in the stack pointed to by the pointer variable.

  5. 5

    However, this expression uses the comparison operator "==" rather than the assignment operator "=". The result of using the comparison operator instead of the assignment operator causes erroneous values to be entered into the stack and can cause unexpected results.

Exemplo de código vulnerável

Vulnerable C

The following C/C++ and C# examples attempt to validate an int input parameter against the integer value 100.

Vulnerável C 
int isValid(int value) {
  	if (value=100) {
  		printf("Value is valid\n");
  		return(1);
  	}
  	printf("Value is not valid\n");
  	return(0);
  }
Exemplo de código seguro

Secure Verilog

A fix to this issue is to only change the privilege level of the processor when both checks are satisfied, i.e., the request has enough privileges (i.e., debug_mode_q is enabled) and the password checking is successful (i.e., umode_i is enabled) [REF-1378].

Seguro Verilog 
module csr_regfile #(
 ...

```
   // check that we actually want to enter debug depending on the privilege level we are currently in
   unique case (priv_lvl_o)
  	 riscv::PRIV_LVL_M: begin
  		 debug_mode_d = dcsr_q.ebreakm;
 ...
  	 riscv::PRIV_LVL_U: begin
  		 debug_mode_d = dcsr_q.ebreaku;
 ...
   assign priv_lvl_o = 
```
(debug_mode_q && umode_i) ? riscv::PRIV_LVL_M : priv_lvl_q;** 
   ...

```
   debug_mode_q <= debug_mode_d;
 ...
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Lista de verificação de prevenção

How to prevent CWE-480

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Sinais de deteção

How to detect CWE-480

Automated Static Analysis

This weakness can be found easily using static analysis. However in some cases an operator might appear to be incorrect, but is actually correct and reflects unusual logic within the program.

Manual Static Analysis

This weakness can be found easily using static analysis. However in some cases an operator might appear to be incorrect, but is actually correct and reflects unusual logic within the program.

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-480 e abre um PR de correção em menos de 60 segundos.

O Codex Remedium analisa cada commit, identifica esta fraqueza exata e entrega um pull request pronto para revisão com o patch. Sem tickets. Sem transferências.

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Perguntas frequentes

Frequently asked questions

O que é o CWE-480?

This vulnerability occurs when a developer mistakenly uses the wrong operator in their code, leading to unintended and potentially insecure logic.

Qual a gravidade do CWE-480?

A MITRE classifica a probabilidade de exploração como Baixa — a exploração é pouco comum, mas a fraqueza deve mesmo assim ser corrigida quando descoberta.

Que linguagens ou plataformas são afetadas pelo CWE-480?

MITRE lists the following affected platforms: C, C++, Perl.

Como posso prevenir o CWE-480?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Como é que o Plexicus deteta e corrige o CWE-480?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-480 em cada commit. Quando é encontrada uma correspondência, o nosso agente Codex Remedium abre um PR de correção com o código corrigido, testes e um resumo de uma linha para o revisor.

Onde posso saber mais sobre o CWE-480?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/480.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

Weaknesses related to CWE-480

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Omitted Break Statement in Switch

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CWE-617 Irmão

Reachable Assertion

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CWE-698 Irmão

Execution After Redirect (EAR)

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CWE-783 Irmão

Operator Precedence Logic Error

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CWE-481 Filho

Assigning instead of Comparing

This flaw occurs when a developer accidentally uses the assignment operator (=) instead of the comparison operator (== or ===). The code…

CWE-482 Filho

Comparing instead of Assigning

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CWE-597 Filho

Use of Wrong Operator in String Comparison

This vulnerability occurs when a developer incorrectly compares string values, typically by using reference equality operators (like == or…

Recursos

Further reading

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