CodeQL zero to hero part 1: The fundamentals of static analysis for vulnerability research

Static analysis is a technique used to examine an application's code for potential errors without executing it, offering checks and highlighting issues. GitHub employs static analysis in its code scanning through CodeQL, a semantic analysis engine. The blog series introduces static analysis concepts, CodeQL, its application in security research, and guides on writing custom CodeQL queries. Static analysis helps identify vulnerabilities like SQL injection by tracing data flow from sources (user inputs) to sinks (functions where vulnerabilities may occur). Early static analysis tools address this by using technologies like lexical analysis and abstract syntax trees (ASTs) to refine detection accuracy. Modern methods, incorporating taint tracking and data flow analysis, further enhance precision by automatically identifying unsafe data flows to dangerous functions. These advancements enable security researchers to efficiently uncover vulnerabilities in code, with CodeQL facilitating the customization of analyses to accommodate specific sanitization methods.