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CWE-822 Base Incompleto
Untrusted Pointer Dereference
This vulnerability occurs when software takes a value from an untrusted source, treats it as a memory address (a pointer), and then accesses that memory location directly for reading or writing.
Definição
What is CWE-822?
This vulnerability occurs when software takes a value from an untrusted source, treats it as a memory address (a pointer), and then accesses that memory location directly for reading or writing.
An attacker can exploit this by providing a pointer to unexpected memory regions. If the software writes to this location, it could corrupt critical data, crash the program, or even allow code execution. If it reads from the location, it might leak sensitive information, cause a crash, or use an arbitrary value from memory, leading to unpredictable behavior.
This weakness appears in several forms. For example, the untrusted value might be called directly as a function pointer. In operating system kernels, untrusted pointers can cross the boundary from user space into privileged memory via system calls. It also often arises when code designed for a trusted, isolated environment is later exposed to untrusted network input without proper validation of pointer values.
Impacto no mundo real
Real-world CVEs caused by CWE-822
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message-passing framework interprets values in packets as pointers, causing a crash.
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labeled as a "type confusion" issue, also referred to as a "stale pointer." However, the bug ID says "contents are simply interpreted as a pointer... renderer ordinarily doesn't supply this pointer directly". The "handle" in the untrusted area is replaced in one function, but not another - thus also, effectively, exposure to wrong sphere (CWE-668).
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Untrusted dereference using undocumented constructor.
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An error code is incorrectly checked and interpreted as a pointer, leading to a crash.
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An untrusted value is obtained from a packet and directly called as a function pointer, leading to code execution.
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Undocumented attribute in multimedia software allows "unmarshaling" of an untrusted pointer.
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ActiveX control for security software accepts a parameter that is assumed to be an initialized pointer.
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Spreadsheet software treats certain record values that lead to "user-controlled pointer" (might be untrusted offset, not untrusted pointer).
Como os atacantes a exploram
Trajeto do atacante passo a passo
- 1
Identificar um caminho de código que trata input não confiável sem validação.
- 2
Criar um payload que explora o comportamento inseguro — injeção, traversal, overflow ou abuso de lógica.
- 3
Entregar o payload através de um pedido normal e observar a reação da aplicação.
- 4
Iterar até que a resposta exponha dados, execute código do atacante ou escale privilégios.
Exemplo de código vulnerável
Vulnerable pseudo
A MITRE não publicou um exemplo de código para este CWE. O padrão abaixo é ilustrativo — consulte os Recursos para referências canónicas.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Exemplo de código seguro
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} 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-822
- 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-822
Executar testes dinâmicos de segurança de aplicações (DAST) contra o endpoint em execução.
Monitorizar os registos em tempo de execução para traços de exceção invulgares, input malformado ou tentativas de contornar a autorização.
Revisão de código: sinalizar qualquer novo código que trate input desta superfície sem usar os ajudantes validados do framework.
CWE-822
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Perguntas frequentes O que é o CWE-822?
Qual a gravidade do CWE-822?
Que linguagens ou plataformas são afetadas pelo CWE-822?
Como posso prevenir o CWE-822?
Como é que o Plexicus deteta e corrige o CWE-822?
Onde posso saber mais sobre o CWE-822?
Frequently asked questions
O que é o CWE-822?
This vulnerability occurs when software takes a value from an untrusted source, treats it as a memory address (a pointer), and then accesses that memory location directly for reading or writing.
Qual a gravidade do CWE-822?
A MITRE não publicou uma classificação de probabilidade de exploração para esta fraqueza. Trate-a como impacto médio até o seu modelo de ameaças provar o contrário.
Que linguagens ou plataformas são afetadas pelo CWE-822?
A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.
Como posso prevenir o CWE-822?
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-822?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-822 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-822?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/822.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
Weaknesses related to CWE-822
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Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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CWE-123 Irmão
Write-what-where Condition
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Out-of-bounds Read
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CWE-130 Irmão
Improper Handling of Length Parameter Inconsistency
This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length…
CWE-466 Irmão
Return of Pointer Value Outside of Expected Range
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CWE-786 Irmão
Access of Memory Location Before Start of Buffer
This vulnerability occurs when software attempts to read from or write to a memory location positioned before the official start of a…
CWE-787 Irmão
Out-of-bounds Write
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CWE-788 Irmão
Access of Memory Location After End of Buffer
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