No software is free from bugs. In practical use, there will be in the bugs, user errors and security errors that the developers have not considered. But with static code analysis, source code can be examined for many vulnerabilities before it is compiled. How this works, which analysis tools you need and why you still can't do without manual analysis, we explain in this article.
What is Static Code Analysis?
Static code analysis involves identifying vulnerabilities within the source code using a variety of techniques. This is done as part of the code review process during implementation, before the code has been compiled into a runnable program. Static code analysis is an important tool within a security development lifecycle. At this early stage, troubleshooting via static code analysis is relatively inexpensive because adjustments can be made more easily than when the program is running.
Techniques in Static Code Analysis
Various techniques are used in static code analysis. In practice, tools combine all these techniques in one interface and are thus able to automatically check a source code for a large number of security vulnerabilities simultaneously.
- Data flow analysis simulates running software in order to collect relevant data about it.
- Taint analysis traces user-controlled variables to functions that could represent security vulnerabilities. Thus, an attacker could pass specific data about the variable as a user and gain access to other areas of the application.
- Lexical analysis transforms the syntax of the code into information tokens. This makes the syntax understandable to the tool. These information tokens are then matched against development standards and manipulated to identify vulnerabilities in.
Tools for Static Code Analysis
For static code analysis, tools are available for each programming language that combine the different techniques of code analysis in one interface. Theoretically, a fully automated static code analysis would be conceivable. It would not only replace the work of the security analyst, but also provide a very high level of security. In practice, however, tools are not yet capable of identifying every type of security vulnerability found in software today. They do not replace the manual work of an analyst, but they help him to systematically check the code and find vulnerabilities more efficiently.
Analyze Java Source Code with Spotbugs and Find Security Bugs
Spotbugs lets you examine the source code of applications written in Java. After installation, the tool, which is available free of charge, examines the code for over 400 different known bugs and security vulnerabilities. Based on Spot Bugs, Find Security Bugs was developed to also examine Java web applications for bugs. Find Security Bugs is available for free download and currently finds 138 different security vulnerabilities. In addition, the tool is available as a plug-in for all common development environments.
Scan C/C++ source code for Security Vulnerabilities with FlawFinder
FlawFinder is the tool for static analysis of code in C and C++. It examines the code for possible security vulnerabilities and outputs them to the user. In doing so, FlawFinder sorts the security risks according to the risk level. FlawFinder is written in Python and can be installed via pip after installation. With a single command, the tool then searches the folder containing the source code.
Check PHP Application Syntax with PHP Code SnifferPHP Code Sniffer is a free open-source script that allows you to check the code of your PHP application against the PEAR standard and correct errors automatically. Installation and use are simple. PHP Code Sniffer is compatible with most editors and can be added as an add-on.
Static Code Analysis: An Indispensable Tool for better Security and higher Software Quality
Static code analysis offers developers the chance to identify and proactively fix relevant security issues before a software is ready to run. Tools exist for every programming language that automatically scan code for various vulnerabilities. However, code analysis is not a panacea. They do not find all security vulnerabilities, so the manual work of a security analyst remains necessary.