What Is SAST? Overview + SAST Tools
SAST and SAST tools are essential as the vast majority of data breaches and other software security incidents occur when attackers exploit vulnerable code in an application.
What's more, SAST tools are some of the most used and essential security testing tools that DevSecOps teams can use in their workflow. To help you understand and make the best out of these tools, we provide an overview of what is SAST and explore what software vulnerabilities SAST tools can detect.
Read along or jump to the section that interests you the most:
- What Is SAST?
- How Does SAST Work?
- What Problems Does SAST Solve?
- What Kind of Vulnerabilities can SAST Tools Detect?
- How to Perform a SAST Test?
- What are the Advantages of SAST Tools?
- What are Common Challenges with Static Application Security Testing?
What Is SAST?
Static application security testing (SAST) is a software testing methodology designed for inspecting and analyzing application source code, byte code, and binaries for coding and design conditions to uncover security vulnerabilities.
Also known as “white-box testing”, SAST tools — such as static code analysis tools — scan your application’s code in a non-running state (before the code is compiled). SAST tools are crucial in the software development space since they detect vulnerabilities that leave systems open to attacks such as:
- Denial of service (DoS).
- Leakage of private data.
- Unauthorized changes to system behavior.
Static application security testing is just one element of a complete automated security testing toolkit. Other tools include:
- Dynamic Analysis Security Testing (DAST).
- Database Security Scanning.
- Mobile Application Security Testing.
- Software Composition Analysis.
- Network Vulnerability Scanning.
Static application security testing and dynamic application security testing are both types of security vulnerability testing, but it's important to understand the differencesSAST vs DAST. Regardless of the differences, a static application security testing tool should be used as the first line of defense.
📕 Related Resource: Review the SAST tutorial for additional resources.
How Does SAST Work?
The working mechanism behind SAST is that a static code analyzer is used to check the source code for design and coding flaws that could make an application vulnerable. While analyzing the source code, the SAST tool will identify several issues ranging from programming errors, unsanitized input processing, vulnerable constructs, and so forth.
The beauty of static application security testing is that you can check for security problems even if the application or system is not complete. Besides application security, SAST is also used to detect bugs, improve code quality, and enforce pre-defined coding standards.
What Problems Does SAST Solve?
At its core, static application security testing is designed to solve three problems:
- Detecting Source-Code Vulnerabilities: The main benefit of SAST tools is that they help developers catch security issues such as SQL injections that could disrupt the availability and integrity of an application’s service.
- Eliminating Late Diagnostics: Late diagnostics of problems in the source code can cause a huge technical debt in software systems. SAST solutions grant users the ability to diagnose the code and make necessary improvements before a release. This reduces the cost of remediating a problem once the application is deployed.
- Enhancing Root-Cause Analysis: Every developer would love to identify problematic areas in their code without having to check through the code manually. With SAST tools, developers get notified about faulty code as well as the exact code segments behind the issue. As illustrated below, SAST tools point out exactly where a problem lies. This means developers spend less time looking for bugs. It also makes remediation a lot easier.
What Kinds of Vulnerabilities can SAST Tools Detect?
Software applications are susceptible to a wide range of security vulnerabilities. These vulnerabilities often vary from one application to another, depending on the programming language, development framework, security models used.
For example, cross-site scripting vulnerabilities are found in around 2/3 of all web applications. Embedded applications written in C are more likely to contain memory corruption bugs that make it possible to exploit the code.
That is why it is important to choose a software security tool that is precisely designed for your application type. Here are some of the most common vulnerabilities that SAST tools can detect.
An SQL injection is a code injection technique used to attack data-driven applications. It occurs when an attacker embeds SQL commands with user-provided parameters.
Here’s an example Java code snippet that is vulnerable to SQL injections.
Input Validation Attacks
An input validation attack is arguably one of the most prevalent security problems out there. It occurs when an attacker deliberately enters malicious input into a system in a bid to execute arbitrary code. This can lead to memory leaks, injection attacks, and other forms of system compromise.
Invalidated user input presents a major security risk, as illustrated in the example below.
Stack Buffer Overflows
Stack buffer overflows are a common software vulnerability that usually occurs when a program writes more data to a buffer located on the stack than what is actually allocated for it.
Buffer overflow can also be caused deliberately as part of an attack known as “stack smashing”. Stack buffer overflow often leads to the corruption of adjacent data on the stack. And, in some cases, it causes the program to crash or operate incorrectly.
Look at the example C program below that is vulnerable to a buffer overflow.
An integer overflow occurs when an arithmetic operation — such as multiplication or addition — exceeds the maximum size of the integer type used to store it. When an integer overflow occurs, it can jeopardize a program’s reliability and security.
Here’s an example Java code snippet demonstrating how an integer overflow can occur.
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How to Perform a SAST Scan?
To perform a SAST scan efficiently, you must follow these steps:
- Select the right static analysis tool. Start by choosing a SAST tool that can analyze code in the languages your applications are written in. For a tool to perform code analysis effectively, it must support the framework used by your application.
- Set up the scanning environment and deploy your tool. Prepare the scanning infrastructure by setting up access controls and authorization mechanisms. You also procure all resources needed to deploy the SAST tool, such as databases and servers.
- Customize the tool. Configure the tool to suit your development needs. For instance, you can write new rules to help detect additional security vulnerabilities. You also need to integrate the SAST tool into your build environment and create dashboards where you can track scan results and generate custom reports.
- Onboard applications for scanning. Once the testing environment is ready, it’s time to onboard your applications. For teams with many applications to scan, consider prioritizing those with the highest risk. However, all applications should be scanned regularly, with scans scheduled, after every code check-in or build event.
- Analyze scan results. After every code scan, you should dig through the scan results to remove all false positives. Once done, you can pass the final set of results to the concerned parties for effective and timely remediation.
The Advantages of SAST Tools
There are many benefits of SAST tools, including:
Automated Vulnerability Detection
The tool examines the code continually throughout the development process and provides an in-depth analysis that identifies defects, vulnerabilities, and compliance issues in the source code.
SAST tools examine your code continually throughout the development process and provide an in-depth analysis for the identification of defects, vulnerabilities, and compliance issues in the codebase. Their output is easily digestible by developers because the tools will point out exactly where a problem lies.
Ease of Integration
The best tools easily integrate into a development team’s established toolset. This protects your development process from delays.
Enhanced Development Velocity
Through static code analysis, you get insights into your code quality on the go. This reduces the disruptions to your development cycle, thereby accelerating your development pace.
Easy to Automate
Static application security testing processes can be easily automated. This allows developers to run scalable tests on their codebase as they wish.
What are Common Challenges with Static Application Security Testing?
SAST solutions unlock plenty of opportunities for development teams. However, they also have their unique share of challenges. Some of the most notable issues include:
Difficulty Setting up SAST Tools
A significant percentage of developers say that the initial set-up process of integrating a SAST tool in the development and build environment, and ensuring things work seamlessly is the most difficult part of using the tool. To minimize this trouble, you should consider the installation factor right before choosing a static analysis tool. The ideal tool should give you a hassle-free set-up experience.
Disruption of Regular Workflow
Some security testing solutions can interrupt your workflow through regular alerts. To minimize distractions, you should choose a tool that allows you to control how alerts are delivered. The best SAST solution should be easy to use and get into the developer’s flow without causing too much invasion.
While this depends on the security tool you’re using, some SAST tools can report a high number of false positives and other unnecessary issues to the developer.
Ability to Support Multiple Programming Languages
Development teams use several programming languages when working on their projects. Targeting each of these languages becomes an issue when using a single static analysis tool.
One SAST Tool Is not Enough — Sometimes
Far too often one tool is not enough to uncover a whole range of weaknesses in your application. However, this depends on your tool’s capability. Sometimes a developer is forced to tradeoff some requirements when choosing a tool. For instance, one tool might be comprehensive but lack broad language support while another that covers multiple languages might have low performance in some of them.
Why Choose Perforce SAST Tools?
What’s more, Klocwork’s Differential Analysis enables teams to perform very fast incremental analysis on only the files that have changed while providing results equivalent to those from a full project scan. This ensures the shortest possible analysis times.
In addition, Klocwork provides software developers with the following benefits:
- Detecting code vulnerabilities, compliance issues, and rule violations earlier in development. This helps to accelerate code reviews as well as the manual testing efforts of developers.
- Enforcing industry and coding standards, including CWE, CERT, and OWASP.
- Reporting on compliance over time and across product versions.
See for yourself how Klocwork can help you identify security vulnerabilities earlier in development. Request your free trial today.