In cybersecurity, a key priority for the “good guys” is discovering security vulnerabilities in software systems before the “bad guys” – meaning threat actors – find and exploit them. To that end, security teams often attempt to interact with applications in the same way that attackers would, hoping to uncover security flaws that might have slipped past earlier security tests.
Historically, simulated attacks against software were known as penetration tests. While automated penetration testing platforms (like Pentera) now exist, they differ from Dynamic Application Security Testing (DAST) solutions. DAST tools focus specifically on web application vulnerabilities and integrate directly into development pipelines, while penetration testing provides broader security assessments by simulating complete attack scenarios.
This doesn’t mean that penetration testing no longer has a role to play; sometimes, pentesting is a better approach than DAST for identifying security risks. To understand what to use when, read on as we break down the similarities and differences between pentesting and DAST.
What is penetration testing?
Penetration testing (pentesting) is the practice of attempting to find and exploit security vulnerabilities or misconfigurations in a live IT environment.
For example, security analysts carrying out a pentest against a Web application might perform actions such as inserting malicious code into application input fields. This is a way of assessing whether the app is vulnerable to what are known as injection attacks, which occur when applications fail to block malicious commands included in user input. Likewise, pentesters in this scenario may run custom JavaScript code on the site to see whether doing so allows them to log in as an admin or superuser. Pentesters may attempt session hijacking, authentication bypass, or privilege escalation using tools like Burp Suite or custom scripts.
Penetration tests also sometimes involve social engineering techniques, meaning attempts by testers to bypass software security controls or obtain sensitive information by convincing humans to hand it over to them. In this way, pentests can analyze whether any “soft” vulnerabilities within an organization – as opposed to “hard” vulnerabilities like flaws in application code – could enable an attack.
There are two basic approaches to pentesting:
- Black box testing: A black box test means that pentesters operate without any insider knowledge of how the system they are testing works. The goal is to simulate how external threat actors might attempt to compromise a system when they can only view it from the outside.
- Gray box testing: Under a gray box test, pentesters have some knowledge of how the system works. They might know which programming language an application was written in, for example, or which type of application architecture it uses. Gray box testing is helpful for simulating how malicious insiders within an organization might attempt to attack software.
What is DAST?
Dynamic Application Security Testing (DAST) is the practice of using software tools to simulate malicious interactions with a system. DAST tools automatically perform actions that mimic those threat actors would carry out – such as exploiting configuration errors, exploiting cross-site scripting vulnerabilities, and injecting malicious code into application input fields.
To run DAST tests, security analysts typically select a DAST tool, and then configure it to perform the tests they want it to run. From there, the tool automatically interacts with the application they are testing and generates a report about any risks or vulnerabilities it identified. Interactions may take the form of direct application input, but they can also involve API requests, since modern DAST solutions support API scanning.
Main similarities between DAST and pentesting
Pentesting and DAST share many similarities, including:
- Methodology: Both techniques employ the same basic method for discovering vulnerabilities: They simulate malicious interactions with IT resources to mimic actual attacks that threat actors might carry out.
- Types of risks detected: The vulnerabilities and other risks that pentests and DAST scans can uncover, such as code injection vulnerabilities or lack of effective access controls, are largely the same.
- Position in software development life cycle: Pentests and DAST scans both typically take place after earlier types of security scans – such as Static Application Security Testing (SAST), which analyzes non-running applications. The main goal of both pentesting and DAST is to catch risks that earlier scans overlooked in running applications. While penetration tests are typically performed late in the SDLC, DAST can be integrated earlier in development—especially within CI/CD pipelines—to continuously assess security in running applications and APIs.
While these techniques share common ground, their fundamental differences define when and how each should be used.
Main differences between DAST and pentesting
DAST is a fully automated security testing approach that continuously assesses running applications, making it well-suited for scalable security testing in CI/CD pipelines. Penetration testing, in contrast, relies on a combination of automated tools and manual expertise to simulate complex multi-step attack scenarios.
We’re saying here that pentesting is “mostly” manual because pentesters often rely on various types of automated scanning tools, such as Burp Suite, Metasploit, Nmap, and fuzzers. These tools automate many of the processes required to collect data about a target and attempt exploits. However, manual expertise is necessary to chain the vulnerabilities together into realistic attack scenarios – something DAST alone cannot do.
For its part, DAST automates much of the scanning process, but it requires security analysts to fine-tune configurations, validate findings, and triage false positives. DAST automates the execution of simulated attacks but it requires manual oversight.
Other, smaller differences exist between pentesting and DAST, too. One is that, as noted above, pentesting can include methods such as social engineering, which is not a part of DAST scans. In addition, while DAST focuses on testing applications for security vulnerabilities, pentesting has historically centered on discovering vulnerabilities that allow attackers to breach a business’s network – although in modern environments, where network perimeters are not as neatly defined, penetration tests may be more application-centric. “While penetration testing initially focused heavily on network security, application pentesting has long been a critical component of security assessments. With modern cloud-native architectures, pentesters increasingly focus on web applications, APIs, and microservices.
The timing of pentesting is also often different from DAST tests. While pentesting is typically a late-stage security activity, DAST can be integrated earlier into CI/CD pipelines, enabling continuous security testing during the software development process.
Pentests vs. DAST: What to use when
Although pentesting is more manual and therefore requires more time and effort, it has certain advantages. Above all, pentesting makes it possible to simulate sophisticated attacks that involve multiple breach techniques. DAST is a somewhat blunter approach because DAST tools can only simulate attacks against applications that exploit vulnerabilities or misconfigurations, rather than also employing techniques like social engineering. These characteristics make pentesting preferable for businesses that want to analyze how a highly sophisticated attack against their IT resources might play out.
On the other hand, DAST is typically the better approach for organizations seeking an efficient, large-scale way of discovering risks that impact applications. The ability to automate DAST scans makes DAST more cost-effective in most cases. It also means that DAST testing can cover a wide range of applications easily, whereas with a pentest, you might need to pick only certain resources to evaluate due to the cost and complexity of carrying out the test.
Keep in mind, too, that pentesting and DAST can go hand-in-hand. For example, an organization might carry out DAST tests on a continuous basis to identify risks in running applications, while also periodically performing penetration tests as a means of assessing how resilient its systems are against more complex attack scenarios.
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