CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

CWE/SANS Top 25 Most Dangerous Software Errors
Home > CWE List > CWE- Individual Dictionary Definition (2.10)  
ID

CWE-501: Trust Boundary Violation

Weakness ID: 501
Abstraction: Base
Status: Draft
Presentation Filter:
+ Description

Description Summary

The product mixes trusted and untrusted data in the same data structure or structured message.

Extended Description

A trust boundary can be thought of as line drawn through a program. On one side of the line, data is untrusted. On the other side of the line, data is assumed to be trustworthy. The purpose of validation logic is to allow data to safely cross the trust boundary - to move from untrusted to trusted. A trust boundary violation occurs when a program blurs the line between what is trusted and what is untrusted. By combining trusted and untrusted data in the same data structure, it becomes easier for programmers to mistakenly trust unvalidated data.

+ Time of Introduction
  • Architecture and Design
+ Applicable Platforms

Languages

All

+ Common Consequences
ScopeEffect
Access Control

Technical Impact: Bypass protection mechanism

+ Demonstrative Examples

Example 1

The following code accepts an HTTP request and stores the username parameter in the HTTP session object before checking to ensure that the user has been authenticated.

(Bad Code)
Example Language: Java 
usrname = request.getParameter("usrname");
if (session.getAttribute(ATTR_USR) == null) {
session.setAttribute(ATTR_USR, usrname);
}
(Bad Code)
Example Language: C# 
usrname = request.Item("usrname");
if (session.Item(ATTR_USR) == null) {
session.Add(ATTR_USR, usrname);
}

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.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class485Insufficient Encapsulation
Development Concepts (primary)699
Seven Pernicious Kingdoms (primary)700
Research Concepts (primary)1000
ChildOfCategoryCategory963SFP Secondary Cluster: Exposed Data
Software Fault Pattern (SFP) Clusters (primary)888
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
7 Pernicious KingdomsTrust Boundary Violation
Software Fault PatternsSFP23Exposed Data
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
7 Pernicious KingdomsExternally Mined
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Demonstrative_Example, Time_of_Introduction
2008-09-08CWE Content TeamMITREInternal
updated Description, Relationships, Other_Notes, Taxonomy_Mappings
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Relationships
2014-06-23CWE Content TeamMITREInternal
updated Description, Other_Notes
2014-07-30CWE Content TeamMITREInternal
updated Relationships, Taxonomy_Mappings

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Page Last Updated: January 18, 2017