Falhas do tipo CWE-476

2.177 resultados

Desreferenciação de ponteiro nulo autenticado

O software permite que um usuário autenticado force a desreferenciação de um ponteiro ou referência nula, tipicamente ao passar valores inesperados ou inválidos a uma função. O aplicativo não valida adequadamente a entrada antes de usá-la, causando falha (crash) ou comportamento indefinido que pode levar a negação de serviço.

Exemplo

Um painel administrativo aceita um ID de usuário para deletar, mas não verifica se esse ID existe no banco antes de acessar seus atributos. Um admin autenticado passa ID=0 ou um valor que não corresponde a nenhum registro, e o código tenta acessar propriedades de um objeto nulo, derrubando a aplicação.

Como mitigar

Sempre valide e verifique que referências/ponteiros são válidos antes de desreferenciar: teste se o objeto existe, se o ID é válido e se está dentro do escopo esperado. Use assertions em desenvolvimento e tratamento de exceções robusto em produção para falhas inesperadas.

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