Executar análise estática (SAST) na base de código à procura do padrão inseguro no fluxo de dados.
CWE-420 Base Rascunho
Unprotected Alternate Channel
This vulnerability occurs when an application secures its main communication path but leaves a backup or alternative channel with weaker or no protection.
Definição
What is CWE-420?
This vulnerability occurs when an application secures its main communication path but leaves a backup or alternative channel with weaker or no protection.
Think of an application that uses strong encryption for its primary web login but sends password reset codes via unencrypted SMS. An attacker can ignore the fortified main door and easily intercept data through this neglected side channel. This creates a false sense of security, as the overall system is only as strong as its weakest point. Developers often focus all their security efforts on the obvious primary path, forgetting that attackers actively seek out these alternate, less-guarded routes.
To prevent this, you must perform a thorough threat model that maps all data flows, not just the primary ones. Apply consistent security controls—like encryption, authentication, and integrity checks—across every channel that handles sensitive data or critical commands. Regularly test both primary and alternate paths during security assessments to ensure your defenses are uniform and comprehensive.
Impacto no mundo real
Real-world CVEs caused by CWE-420
-
When the internal flash is protected by blocking access on the Data Bus (DBUS), it can still be indirectly accessed through the Instruction Bus (IBUS).
-
DB server assumes that local clients have performed authentication, allowing attacker to directly connect to a process to load libraries and execute commands; a socket interface also exists (another alternate channel), so attack can be remote.
-
Product does not restrict access to underlying database, so attacker can bypass restrictions by directly querying the database.
-
User can avoid lockouts by using an API instead of the GUI to conduct brute force password guessing.
-
FTP service can not be disabled even when other access controls would require it.
-
Windows named pipe created without authentication/access control, allowing configuration modification.
-
Router management interface spawns a separate TCP connection after authentication, allowing hijacking by attacker coming from the same IP address.
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 Verilog
assign addr_auth = (address == 32'hF00) ? 1: 0; Exemplo de código seguro
Secure Verilog
The bugged line of code is repeated in the Bad example above. The weakness arises from the fact that the SECURE_ME register can be modified by writing to the shadow register COPY_OF_SECURE_ME. The address of COPY_OF_SECURE_ME should also be included in the check. That buggy line of code should instead be replaced as shown in the Good Code Snippet below.
assign addr_auth = (address == 32'hF00 || address == 32'h800F00) ? 1: 0; 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-420
- Architecture and Design Identify all alternate channels and use the same protection mechanisms that are used for the primary channels.
Sinais de deteção
How to detect CWE-420
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.
O Plexicus deteta automaticamente o CWE-420 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.
Perguntas frequentes O que é o CWE-420?
Qual a gravidade do CWE-420?
Que linguagens ou plataformas são afetadas pelo CWE-420?
Como posso prevenir o CWE-420?
Como é que o Plexicus deteta e corrige o CWE-420?
Onde posso saber mais sobre o CWE-420?
Frequently asked questions
O que é o CWE-420?
This vulnerability occurs when an application secures its main communication path but leaves a backup or alternative channel with weaker or no protection.
Qual a gravidade do CWE-420?
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-420?
A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.
Como posso prevenir o CWE-420?
Identify all alternate channels and use the same protection mechanisms that are used for the primary channels.
Como é que o Plexicus deteta e corrige o CWE-420?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-420 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-420?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/420.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
Weaknesses related to CWE-420
CWE-923 Pai
Improper Restriction of Communication Channel to Intended Endpoints
This vulnerability occurs when a system opens a communication channel for a sensitive task but fails to properly verify that it's actually…
CWE-1275 Irmão
Sensitive Cookie with Improper SameSite Attribute
This vulnerability occurs when a sensitive cookie does not have a secure SameSite attribute configured, leaving it exposed to cross-site…
CWE-291 Irmão
Reliance on IP Address for Authentication
This vulnerability occurs when a system uses a client's IP address as the sole or primary method to verify their identity.
CWE-297 Irmão
Improper Validation of Certificate with Host Mismatch
This vulnerability occurs when an application accepts a valid SSL/TLS certificate without properly verifying that it actually belongs to…
CWE-300 Irmão
Channel Accessible by Non-Endpoint
This vulnerability occurs when a system fails to properly verify who is on the other end of a communication link or to secure the channel…
CWE-419 Irmão
Unprotected Primary Channel
This vulnerability occurs when an application exposes a privileged administrative interface or restricted functionality through a primary…
CWE-940 Irmão
Improper Verification of Source of a Communication Channel
This vulnerability occurs when an application accepts incoming communication requests without properly checking where they originate from,…
CWE-941 Irmão
Incorrectly Specified Destination in a Communication Channel
This vulnerability occurs when an application establishes an outgoing communication channel but fails to correctly define or enforce the…
CWE-942 Irmão
Permissive Cross-domain Security Policy with Untrusted Domains
This vulnerability occurs when a web application's cross-domain security policy, like a Content Security Policy (CSP), explicitly allows…
Pronto quando você estiver
Pare de pagar por desenvolvedor.
Comece a fechar o ciclo.
O Plexicus é o ASPM nativo de IA que verifica, filtra, corrige, pentesta e explica — de forma autónoma. Programadores ilimitados, repos ilimitados, ações de IA de utilização justa. Nível gratuito real, €269/mo anual quando estiver pronto.