ABSTRACT

Without proper access control, executing a SQL statement that contains a user-controlled primary key can allow an attacker to view unauthorized records.

EXPLANATION

Database access control errors occur when:

1. Data enters a program from an untrusted source.


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

Example 1: The following code uses a statement that relies on an integer and thus is not vulnerable to 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.


DATA: id TYPE i.
...
id = request->get_form_field( 'invoiceID' ).

CONCATENATE `INVOICEID = '` id `'` INTO cl_where.
SELECT *
FROM invoices
INTO CORRESPONDING FIELDS OF TABLE itab_invoices
WHERE (cl_where).
ENDSELECT.
...


The problem is that the developer has failed to consider 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.

REFERENCES

[1] Standards Mapping - OWASP Top 10 2004 - (OWASP 2004) A2 Broken Access Control

[2] Standards Mapping - OWASP Top 10 2007 - (OWASP 2007) A4 Insecure Direct Object Reference

[3] Standards Mapping - OWASP Top 10 2010 - (OWASP 2010) A4 Insecure Direct Object References

[4] Standards Mapping - FIPS200 - (FISMA) AC

[5] Standards Mapping - Security Technical Implementation Guide Version 3 - (STIG 3) APP3510 CAT I

[6] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 566

[7] Standards Mapping - Web Application Security Consortium 24 + 2 - (WASC 24 + 2) Insufficient Authorization

[8] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 - (PCI 1.1) Requirement 6.5.2

[9] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 - (PCI 1.2) Requirement 6.5.4

[10] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 - (PCI 2.0) Requirement 6.5.8

[11] S. J. Friedl SQL Injection Attacks by Example