Kingdom: API Abuse

An API is a contract between a caller and a callee. The most common forms of API abuse are caused by the caller failing to honor its end of this contract. For example, if a program fails to call chdir() after calling chroot(), it violates the contract that specifies how to change the active root directory in a secure fashion. Another good example of library abuse is expecting the callee to return trustworthy DNS information to the caller. In this case, the caller abuses the callee API by making certain assumptions about its behavior (that the return value can be used for authentication purposes). One can also violate the caller-callee contract from the other side. For example, if a coder subclasses SecureRandom and returns a non-random value, the contract is violated.

System Field Overwrite

ABAP

Abstract

Overwriting system fields can destabilize the normal running of the system.

Explanation

ABAP system fields are always available in ABAP programs. The runtime system fills them according to context after starting a program, after sending a screen and after changing the internal mode. They can then be used in programs to query the system status. System fields are variables but should always be treated as though they were constants and be read only. Changing their values can cause the loss of important information necessary for the flow of the program. Only a limited few of these are meant to be changed within customer ABAP programs.

Changing values of system fields that communicate runtime specific information to the ABAP program could cause disruption or unexpected behavior in the ABAP program.

References

[1] ABAP System Fields SAP

[2] Standards Mapping - Common Weakness Enumeration CWE ID 642

[3] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-001094

[4] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data

[5] Standards Mapping - NIST Special Publication 800-53 Revision 4 SC-5 Denial of Service Protection (P1)

[6] Standards Mapping - NIST Special Publication 800-53 Revision 5 SC-5 Denial of Service Protection

[7] Standards Mapping - OWASP Top 10 2021 A04 Insecure Design

[8] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002400 CAT II

[9] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002400 CAT II

[10] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002400 CAT II

desc.structural.abap.system_field_overwrite