How to build a strong business case for replacing legacy DAST with a modern solution —a practical guide

Legacy DAST tools have long been a component in product security programs, but many have become outdated today. Traditional DAST tools were built for yesterday’s web, often providing only basic web scan results and struggling with modern languages like GraphQL or React JS​. They tend to be slow, noisy, and used mainly as a compliance checkbox rather than as truly useful tools by security leadership.

Luckily, the community's opinion is gradually changing, but updating the legacy DAST solution with a modern DAST one is never easy and requires a compelling business case tailored to your organization’s priorities.

If you're currently required to tick the DAST checkbox for your current compliance and customer needs, you already have justification to evaluate a modern solution that integrates into your modern technology stack and developer workflows, improving rigor and removing friction (and redundancies in cost and effort)

Whether your goal is reducing security risks, improving developer productivity, or consolidating security tools, aligning your justification with measurable business impact will increase your chances of leadership buy-in if you need to make a switch.

The question isn't really "Are DAST tools any good?" but "When are DAST tools worth the investment?"That question brings up things like the maturity of your security program, the capacity of your team(s), and the accuracy and coverage of your documentation, - Nathan Cooke, Manager of Product Security, Alloy

In this guide, we’ll walk through how to articulate the pain points of legacy tools, highlight how modern DAST can address them to different stakeholders, how to justify extra time for evaluating new tools, back it up with real-world use cases, and present a compelling, ROI-driven argument that resonates with everyone!

Pain points of legacy DAST: How to frame them to different stakeholders

If you're reading this article, odds are high that you're already realizing why change is needed. It's probably either excessive noise, no support for GraphQL, lack of API discovery, or poor integration with development workflows. But understanding the pain isn't enough—you need buy-in from multiple stakeholders. In this section, we’ll outline the key pain points of legacy DAST and how to frame them effectively to CISOs, CIOs, and engineering teams to drive alignment.

Basic Results (Lack of Depth & Accuracy)

Pain: Legacy DAST tools miss critical business logic flaws (e.g., BOLA, IDOR Access Control issues...) and generate excessive false positives, making it hard to trust findings.

How to frame it to CISOs:
"Security teams waste time triaging noise instead of fixing real risks. Plus, attackers don’t exploit missing headers—they go after logic flaws that legacy DAST can’t detect. We need a tool that finds the vulnerabilities that can actually lead to breaches."

How to frame it to Engineering leaders:
"False positives slow down release of apps in prod and erode trust in what we're trying to achieve. When your team doesn’t trust the tool and has a huge backlog of tickets from our side, they ignore it. A new modern DAST will give visibility into the most business-critical issues—so when a vulnerability is flagged, it actually matters for your team to fix."

Slow Execution (Delayed Feedback Loops)

Pain: Traditional DAST scans like Qualys DAST (based on the feedback) take hours or days, creating bottlenecks that disrupt agile workflows and delay remediation.

How to frame it to CISOs:
"Long scan times mean vulnerabilities go undetected for too long, increasing risk exposure. A faster solution enables quicker detection of critical vulnerabilities, reducing the window of opportunity for attackers."

How to frame it to Engineering leaders:
"If scans take too long and can't be well integrated in CI/CD, your teams either skip them or delay releases. We need a DAST that provides results quickly and integrates seamlessly into CI/CD."

No API Discovery & Testing

Pain: Legacy DAST tools don’t automatically find and build a detailed inventory of APIs to test, leaving you in the unknown of what's being exposed and actually needs testing.

How to frame it to CISOs:
"APIs are the biggest attack vector today, yet our current DAST doesn’t even see them—we have to rely on what the development team provides us. A modern DAST will help us remove shadow API risks, discover all exposed and internal APIs, test them dynamically, and prevent data leaks before they happen."

How to frame it to Engineering leaders:
"APIs are a core part of our architecture, yet we can't test them properly. We need a tool that maps our API inventory automatically, and you won't need to do extra work of maintaining OpenAPI specs because the tool will also generate OpenAPI schemas automatically".

Difficult Integrations with Developer Workflows

Pain: Legacy DAST operates in silos, requiring manual setup and failing to integrate into CI/CD, making security a blocker instead of an enabler.

How to frame it to CISOs/CIOs:
"Security should be frictionless. If our tools don’t fit into engineering workflows, let's face it—they won’t get used. We need a modern DAST that integrates with our CI pipeline and ticketing system seamlessly, and you get to monitor all results in a single pane of glass with the help of tools like Wiz, which also integrates with modern DAST solutions. "

How to frame it to Engineering leaders:
"If security isn’t automated in CI/CD, you and me both know that developers will ignore it, or it can become a last-minute fire drill. A modern DAST will run seamlessly in your pipeline, giving developers instant, actionable feedback inside their workflow."

Justifying the time investment for evaluating a new DAST

If you’re leading an AppSec team, you’re already juggling security risks, developer enablement, and leadership expectations. The idea of adding yet another tool evaluation might feel like a distraction. But the reality is: sticking with an ineffective DAST is costing more time than evaluating a better one.

But how can you prove that making the switch is worth the time? The key to getting buy-in is demonstrating that a short, structured evaluation now will save significantly more time and effort in the long run. Traditional DAST tools can take 12 hours per scan on average, forcing teams to choose between meeting deadlines or running security tests. In contrast, modern solutions deliver results 5-10x faster, keeping up with agile development.

To C-level leadership, you can frame it as follows — We’ll allocate a focused 4-6 week evaluation on 2-3 critical applications, but the long-term time savings in security team's efficiency, developer productivity, and reduced risk make this a high-ROI investment.

Below is an example of how you can translate the ROI to the leadership based on the engineering team's productivity. You need to estimate the following:

• Number of your developers (ex. 400)
• Hours spent per month fixing critical security issues per developer (ex. 2)
• Percentage of wrongly prioritized vulnerabilities (ex. 30%)
• Your average Engineer's hourly salary (ex. $111,000 (yearly salary/2080)

Multiply these values to estimate Annual Cost of Non-Core Developer Activities.

Then, apply Assumed % improvement from the previous state without selected DAST (ex. 40% for the vulnerability prioritization) before and after.

It'll also help you estimate the percentage of vulnerabilities that are correctly accepted or ignored.

Then, calculate the final difference between the two states to obtain the $ value of total Productivity Improvement Cost Savings.

Budget Justification Angle:

• By replacing our legacy DAST, we can reduce wasted engineering time by X hours per week, saving $Y annually in developer productivity

Instead of spending months dealing with security inefficiencies, investing a few weeks in testing a modern DAST can eliminate thousands of wasted engineering hours per year, close API security gaps, and accelerate security processes without slowing down development.

How to plan your evaluation step-by-step

The key to a successful evaluation is keeping it focused, measurable, and relevant to your organization’s needs. A drawn-out, unstructured test will create resistance, while a short, results-driven pilot will make your case stronger.

Set clear success criteria

Before testing a modern DAST, define what "better" means in your specific environment. Does it mean faster scans, business logic testing, better API security, fewer false positives, or full CI/CD integration?

For each success criteria, define the target metric (if applicable), and priority.You can divide success criteria into sections that you need.
For example,

• Success criteria: Coverage and Accuracy: False positive rate -> Target metric: ≤10%, Priority: High.
• Success criteria: Platform supports custom tests and rules, including from pentest results / incidents, Priority: High.
• Success criteria: Actionability for Developers: The platform provides remediation developers can act on (and customized output in their framework of choice), Priority: High.

Put all modern DAST vendors you're planning to evaluate side by side, and define if each vendor exceeds, meets or does not meet these criteria.

Set time and scope constraints

A well-executed 2-4 week pilot is more effective than an open-ended evaluation. Keep it targeted and results-driven:

• Choose 1-5 critical applications (e.g., an API-heavy app, a customer-facing app).
• Compare results from your modern DAST with your legacy tool—track the speed, depth, and accuracy of findings.
• Involve security & engineering teams from the start—gather feedback on usability and workflow integration.

Measure tangible improvements

Once the pilot runs, collect hard data to justify the switch:

• How much faster are scans? (e.g., scan time reduced from 12 hours → 45 minutes)
• How many critical vulnerabilities were found that legacy DAST missed?
• How significantly did the false positive rate drop? (e.g., from 45% to 10%, saving X developer hours per month)
• How well did it integrate into developer workflows? (e.g., automatic ticketing, real-time Slack alerts)

These numbers will directly support your ROI case to executives.

When you need to present your findings to the broader set of stakeholders, especially to the leadership, align them with broader company priorities:

• If your organization is preparing for an IPO, highlight how stronger security and compliance impact market confidence.
• If cloud adoption is a priority, emphasize how a modern DAST supports API security in cloud-native environments.

Change management: How to present a roll-out plan that ensures minimal disruption

Replacing a security tool can cause friction if not handled correctly. The best approach? A structured, phased rollout that ensures adoption with minimal disruption.

1. Provide a clear implementation roadmap

Instead of overwhelming teams with a sudden switch, plan a phased rollout:

This structured plan ensures a smooth transition while demonstrating quick wins early in the process.

Highlight any vendor support services that will assist the rollout. For example, Escape team usually helps to migrate any previously built custom security tests that would be still required.

Overall, this plan shows stakeholders that there won’t be a chaotic switch — instead, it will be a phased, well-managed project.

2. Minimize the learning curve with strong developer enablement

• Leverage vendor training & documentation – Ensure security & engineering teams can ramp up in days, not weeks (as we've seen in case studies from companies that onboarded modern DAST tools with minimal training). For example, because of a quick and efficient onboarding and training with French Football federation, Escape has not only improved their API visibility, but also improved the way their development teams approach security early in projects.
• Start with security champions – Identify developers who can advocate for the tool internally.
• Automate as much as possible – Integrate scans directly into CI/CD, reducing manual setup and increasing adoption.

3. Communicate the value & keep stakeholders aligned

Proactively address concerns before they arise:

• Executives: Emphasize risk reduction, compliance, and time savings → "This eliminates $X in wasted developer time annually."
• Engineering: Highlight better developer experience & faster triage → "Security findings will now be actionable, with fewer false positives."
• The rest of your security team: Focus on scalability & automation → "This lets us test APIs properly and reduce our manual workload."

How to justify objections from different stakeholders

When presenting a budget request for a modern DAST, decision-makers may challenge the assumptions behind cost savings and ROI projections. Here’s how to address common objections:

"Aren’t these productivity gains just theoretical?"

• Quantify actual engineering hours spent on triaging false positives, configuring legacy DAST tools, and manually fixing security issues.
• Provide internal feedback from security and development teams on inefficiencies caused by the current toolset.
• Compare with published efficiency metrics from companies that have successfully implemented modern DAST solutions.

"Why can't we just improve our existing DAST instead of replacing it?"

• Outline specific limitations of the legacy tool (e.g., lack of GraphQL API support, poor SPA testing, high false-positive rates).
• Demonstrate how patchwork fixes or additional manual workarounds increase costs rather than solving the underlying issues.
• Show how modern DAST solutions integrate better with CI/CD pipelines, improving security automation and response times.

"Can’t we use other security tools (e.g., SAST, CSPM) instead?"

• Highlight how modern DAST solutions offer API security testing and compliance automation, reducing the need for separate tools.
• Explain how DAST provides real-world security insights that other tools, such as Static Application Security Testing (SAST) or Cloud Security Posture Management (CSPM), cannot.
• Demonstrate cost savings from consolidating multiple security functions into a single, modernized DAST solution.

Checklist — How to build a strong business case for replacing legacy DAST

Making the case for replacing a legacy DAST requires more than just highlighting its flaws—you need a structured approach to align stakeholders, quantify the benefits, and present a clear implementation plan. Whether you’re addressing CISOs, engineering leads, or executive decision-makers, this checklist provides a step-by-step framework to ensure your proposal is data-driven, actionable, and tailored to business priorities:

Conclusion

If you're leading AppSec, you already know that your legacy DAST isn’t keeping up. It’s slow, noisy, and missing the vulnerabilities that actually matter. But knowing the problem isn’t enough—you need to get leadership and engineering teams on board with a better solution.

The key? Make it about them. Show leadership how a modern DAST cuts costs and reduces security risks. Show developers how it integrates into their workflow and saves them time. Show your team how it makes security easier, not harder.

A structured business case isn’t just a formality—it’s how you get real change to happen. Take the first step: run a focused evaluation, measure the impact, and prove the ROI. Security doesn’t have to slow development down. With the right DAST, it can actually make everything run faster, smoother, and more secure.

💡 Want to discover more?

• What is wrong with the current state of DAST? Feedback from my conversations with AppSec Engineers
• Top Qualys Alternative: Escape vs Qualys
• We benchmarked DAST products, and this is what we learned