KASTroid is a static analysis and modeling tool that can detect potential tainted dataflows in Kotlin apps. The approach uses a related TXL paradigm called cascaded markup. The algorithm starts with marking sink statements, analyzing them recursively, finding and marking statements which directly influence them and then those that influence those statements, and so on until a fixed point is reached. This fixed point occurs when a potential tainted source is identified or when no more propagation can be done. The process is done directly on the source code which increases the speed required for the process.