Common Weakness Enumeration

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CWE-566: Authorization Bypass Through User-Controlled SQL Primary Key

Authorization Bypass Through User-Controlled SQL Primary Key
Weakness ID: 566 (Weakness Variant)Status: Incomplete
+ Description

Description Summary

The software uses a database table that includes records that should not be accessible to an actor, but it executes a SQL statement with a primary key that can be controlled by that actor.

Extended Description

When a user can set a primary key to any value, then the user can modify the key to point to unauthorized records.

Database access control errors occur when:

  • Data enters a program from an untrusted source.

  • The data is used to specify the value of a primary key in a SQL query.

  • The untrusted source does not have the permissions to be able to access all rows in the associated table.

+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Applicable Platforms

Technology Classes

Database-Server: (Often)

+ Common Consequences

Technical Impact: Read application data; Modify application data; Bypass protection mechanism

+ Demonstrative Examples

Example 1

The following code uses a parameterized statement, which escapes metacharacters and prevents SQL injection vulnerabilities, to construct and execute a SQL query that searches for an invoice matching the specified identifier [1]. The identifier is selected from a list of all invoices associated with the current authenticated user.

(Bad Code)
Example Language: C# 
conn = new SqlConnection(_ConnectionString);
int16 id = System.Convert.ToInt16(invoiceID.Text);
SqlCommand query = new SqlCommand( "SELECT * FROM invoices WHERE id = @id", conn);
query.Parameters.AddWithValue("@id", id);
SqlDataReader objReader = objCommand.ExecuteReader();

The problem is that the developer has not considered all of the possible values of id. Although the interface generates a list of invoice identifiers that belong to the current user, an attacker can bypass this interface to request any desired invoice. Because the code in this example does not check to ensure that the user has permission to access the requested invoice, it will display any invoice, even if it does not belong to the current user.

+ Potential Mitigations

Phase: Implementation

Assume all input is malicious. Use a standard input validation mechanism to validate all input for length, type, syntax, and business rules before accepting the data. Use an "accept known good" validation strategy.

Phase: Implementation

Use a parameterized query AND make sure that the accepted values conform to the business rules. Construct your SQL statement accordingly.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness BaseWeakness Base639Authorization Bypass Through User-Controlled Key
Development Concepts (primary)699
Research Concepts (primary)1000
ChildOfCategoryCategory896SFP Cluster: Tainted Input
Software Fault Pattern (SFP) Clusters (primary)888
+ Content History
Submission DateSubmitterOrganizationSource
Externally Mined
Modification DateModifierOrganizationSource
updated Potential_Mitigations, Time_of_Introduction
updated Relationships, Other_Notes, Taxonomy_Mappings
updated Demonstrative_Examples, Description, Other_Notes, Potential_Mitigations, Taxonomy_Mappings
updated Description
updated Applicable_Platforms, Demonstrative_Examples, Name
updated Common_Consequences
updated Relationships
Previous Entry Names
Change DatePrevious Entry Name
2011-03-29Access Control Bypass Through User-Controlled SQL Primary Key
Page Last Updated: June 23, 2014