OWASP Mobile Top 10 - M4: Insufficient Input/Output Validation

Threat Overview:

Failure to validate and sanitize user input and output can expose mobile apps to critical attacks like SQL injection, command injection, and XSS. This can lead to unauthorized access, data breaches, system compromise, and application disruption.

Attack Vectors:

• Exploitability: Difficult
• Prevalence: Common
• Detectability: Easy

Impacts:

• Technical: Code execution, data breaches, system compromise, and app crashes.
• Business: Reputation damage, legal liabilities, regulatory penalties, and financial losses.

Vulnerability Indicators:

• Lack of input validation and output sanitization
• Context-specific validation neglect (e.g., path traversal)
• Weak secure coding practices (e.g., missing parameterized queries)

Prevention:

• Validate and sanitize all inputs/outputs.
• Use output encoding to prevent XSS.
• Implement strict context-based validation.
• Ensure data integrity checks.
• Follow secure coding practices like prepared statements.
• Conduct regular security testing.

Example Attack Scenarios:

1. Remote Code Execution: Malicious input bypasses validation, leading to code execution and data access.
2. Injection Attacks: Unvalidated output enables XSS or SQL injection.
3. Malformed Output Exploitation: Specially crafted data triggers unintended actions, granting attacker control.