CRITICAL
								
				
				
				
								
				Rule Definition
				Without well-established and maintained trust boundaries, programmers will inevitably lose track of which pieces of data have been validated and which have not. This confusion will eventually allow some data to be used without first being validated.				
								
				
				Remediation
				Perform input data validation before storing or transmitting the data.				
												
				 Violation Code Sample
				
				String usrname;  // value given by an API request
if (session.getAttribute(ATTR_USR) == null) {
    session.setAttribute(ATTR_USR, usrname);
}
				 
												 Fixed Code Sample
				
				// Never mix trusted and untrusted data
				 
												
				Reference
				CWE-501: Trust Boundary Violation
https://cwe.mitre.org/data/definitions/501.html
Open Web Application Security Project (OWASP)
https://www.owasp.org/index.php/Top_10-2017_A3-Sensitive_Data_Exposure
								
				 Related Technologies
								
				
				
				
				Technical Criterion
				Secure Coding - Input Validation
				
				
				
				
				
					
				
				
				
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