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CWE-799 Classe Incompleto
Improper Control of Interaction Frequency
This vulnerability occurs when an application fails to properly restrict how often or how many times a user or automated system can interact with it.
Definição
What is CWE-799?
This vulnerability occurs when an application fails to properly restrict how often or how many times a user or automated system can interact with it.
Without proper frequency limits, both human users and automated bots can perform actions far more often than intended. This flaw is commonly exploited to launch denial-of-service (DoS) attacks, bypass business logic (like voting systems or promotional offers), or brute-force credentials by making unlimited password attempts.
Developers must implement controls like rate limiting, request throttling, and CAPTCHAs to enforce interaction boundaries. These measures are essential for protecting system availability, ensuring fair use, and preventing automated tools from exploiting core application functions.
Impacto no mundo real
Real-world CVEs caused by CWE-799
-
Mail server allows attackers to prevent other users from accessing mail by sending large number of rapid requests.
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 C
In the following code a username and password is read from a socket and an attempt is made to authenticate the username and password. The code will continuously checked the socket for a username and password until it has been authenticated.
char username[USERNAME_SIZE];
char password[PASSWORD_SIZE];
while (isValidUser == 0) {
if (getNextMessage(socket, username, USERNAME_SIZE) > 0) {
if (getNextMessage(socket, password, PASSWORD_SIZE) > 0) {
isValidUser = AuthenticateUser(username, password);
}
}
}
return(SUCCESS); Exemplo de código seguro
Secure C
This code does not place any restriction on the number of authentication attempts made. There should be a limit on the number of authentication attempts made to prevent brute force attacks as in the following example code.
int count = 0;
while ((isValidUser == 0) && (count < MAX_ATTEMPTS)) {
if (getNextMessage(socket, username, USERNAME_SIZE) > 0) {
if (getNextMessage(socket, password, PASSWORD_SIZE) > 0) {
isValidUser = AuthenticateUser(username, password);
}
}
count++;
}
if (isValidUser) {
return(SUCCESS);
}
else {
return(FAIL);
} 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-799
- 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-799
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-799
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-799?
Qual a gravidade do CWE-799?
Que linguagens ou plataformas são afetadas pelo CWE-799?
Como posso prevenir o CWE-799?
Como é que o Plexicus deteta e corrige o CWE-799?
Onde posso saber mais sobre o CWE-799?
Frequently asked questions
O que é o CWE-799?
This vulnerability occurs when an application fails to properly restrict how often or how many times a user or automated system can interact with it.
Qual a gravidade do CWE-799?
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-799?
A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.
Como posso prevenir o CWE-799?
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-799?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-799 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-799?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/799.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
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