In SAP ABAP development, input validation is a critical security measure that prevents malicious data from entering SAP systems. Poor validation can lead to security breaches such as SQL injection, cross-site scripting (XSS), buffer overflow, and unauthorized data manipulation — collectively referred to as SAP crimes in the cybersecurity context.
This article outlines the best practices for input validation in SAP ABAP to build secure, robust applications and safeguard sensitive enterprise data.
Input validation ensures that all data entering the system is:
- Correct in type, format, and range.
- Free from malicious or harmful content.
- Compliant with business rules and logic.
Failing to validate inputs effectively opens doors for attackers to exploit SAP applications.
¶ A. Use Strong Typing and Domain Restrictions
- Leverage ABAP Dictionary domains and data elements to enforce data types, lengths, and value ranges.
- Define fixed formats or value tables where applicable.
- This reduces errors at the data definition level before runtime.
- Perform validation as soon as data is received — in user input screens, API calls, or external interfaces.
- Avoid relying solely on client-side validation; always validate on the server side in ABAP.
- Implement regex checks (
CL_ABAP_REGEX) to enforce format constraints such as emails, phone numbers, or IDs.
- Reject any inputs that do not strictly conform to expected patterns.
¶ D. Avoid Dynamic SQL and Use Parameterized Queries
- Never concatenate user input directly into Open SQL statements.
- Use host variables and parameterized queries to prevent SQL injection.
- Remove or escape special characters, control sequences, and HTML/JavaScript tags if inputs are displayed in web UIs.
- Use built-in SAP escaping mechanisms to prevent cross-site scripting attacks.
¶ F. Check for Null and Boundary Conditions
- Always check if inputs are non-empty before processing.
- Validate numeric inputs against minimum and maximum allowed values.
- Verify date fields to ensure valid and logical date ranges.
- Create reusable validation classes or function modules to maintain consistency and reduce errors.
- This approach simplifies maintenance and enhances security.
¶ H. Use Exception Handling
- Validate inputs and raise meaningful exceptions if data does not comply.
- This prevents further processing of bad data and allows controlled error handling.
- Logging and Monitoring: Record invalid input attempts and analyze logs for suspicious activities.
- Authorization Checks: Ensure that input data complies with user permissions and roles.
- Regular Code Reviews: Periodically audit ABAP code for input validation gaps and vulnerabilities.
- Relying solely on client-side validation (e.g., JavaScript).
- Overlooking input from external interfaces (IDocs, BAPIs).
- Using overly broad regex patterns that allow unsafe inputs.
- Ignoring boundary cases like empty strings or excessively long inputs.
DATA: lv_input TYPE string,
lo_regex TYPE REF TO cl_abap_regex,
lo_matcher TYPE REF TO cl_abap_matcher,
lv_valid TYPE abap_bool.
lv_input = 'user@example.com'.
TRY.
lo_regex = cl_abap_regex=>create( pattern = '^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$' ).
lo_matcher = lo_regex->create_matcher( text = lv_input ).
lv_valid = lo_matcher->match( ).
CATCH cx_sy_regex_error.
lv_valid = abap_false.
ENDTRY.
IF lv_valid = abap_true.
WRITE: / 'Input is valid'.
ELSE.
WRITE: / 'Input is invalid'.
ENDIF.
Input validation is a frontline defense against SAP security crimes. By applying best practices such as strong typing, regex validation, parameterized queries, and input sanitization, ABAP developers can build resilient SAP applications. These safeguards maintain data integrity, protect sensitive information, and ensure compliance with enterprise security policies.
Robust input validation is not just good programming—it's essential for protecting SAP landscapes in today’s security-conscious world.