Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-925 Variante Incompleto
Improper Verification of Intent by Broadcast Receiver
This vulnerability occurs when an Android app's Broadcast Receiver accepts an Intent without confirming it originated from a trusted, authorized source, such as the operating system.
Definição
What is CWE-925?
This vulnerability occurs when an Android app's Broadcast Receiver accepts an Intent without confirming it originated from a trusted, authorized source, such as the operating system.
Android allows apps to register Broadcast Receivers for specific system-generated Intents, like a device boot completion. These are implicit intents that, by design, should only be sent by the OS. However, the same receiver registration also accepts explicit intents, which can be crafted and sent by any app on the device.
A malicious app can exploit this by sending a carefully crafted explicit intent to the receiver. If the receiving app fails to verify the intent's source, it may incorrectly process the malicious intent as a legitimate system broadcast. This confusion can trigger unauthorized actions, expose sensitive data, or crash the application.
Impacto no mundo real
Real-world CVEs caused by CWE-925
Ainda não há referências CVE públicas associadas a este CWE no catálogo da MITRE.
Como os atacantes a exploram
Trajeto do atacante passo a passo
- 1
The following example demonstrates the weakness.
- 2
The ShutdownReceiver class will handle the intent:
- 3
Because the method does not confirm that the intent action is the expected system intent, any received intent will trigger the shutdown procedure, as shown here:
- 4
An attacker can use this behavior to cause a denial of service.
Exemplo de código vulnerável
Vulnerable XML
The following example demonstrates the weakness.
<manifest package="com.example.vulnerableApplication">
<application>
```
...*
```
<receiver android:name=".ShutdownReceiver">
<intent-filter>
<action android:name="android.intent.action.ACTION_SHUTDOWN" />
</intent-filter>
</receiver>
```
...*
</application></manifest> Payload do atacante
Because the method does not confirm that the intent action is the expected system intent, any received intent will trigger the shutdown procedure, as shown here:
window.location = examplescheme://method?parameter=value 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-925
- Architecture and Design Before acting on the Intent, check the Intent Action to make sure it matches the expected System action.
Sinais de deteção
How to detect CWE-925
CWE-925
Don't catalog this weakness. Prove it's reachable.
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Perguntas frequentes O que é o CWE-925?
Qual a gravidade do CWE-925?
Que linguagens ou plataformas são afetadas pelo CWE-925?
Como posso prevenir o CWE-925?
Como é que o Plexicus deteta e corrige o CWE-925?
Onde posso saber mais sobre o CWE-925?
Frequently asked questions
O que é o CWE-925?
This vulnerability occurs when an Android app's Broadcast Receiver accepts an Intent without confirming it originated from a trusted, authorized source, such as the operating system.
Qual a gravidade do CWE-925?
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-925?
MITRE lists the following affected platforms: Mobile.
Como posso prevenir o CWE-925?
Before acting on the Intent, check the Intent Action to make sure it matches the expected System action.
Como é que o Plexicus deteta e corrige o CWE-925?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-925 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-925?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/925.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
Weaknesses related to CWE-925
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