Episode 32 — Build Application Security Testing Strategy: SAST, DAST, SCA, and Triage

In this episode, we take a practical approach to application security testing, because testing only improves security when it produces signals teams can trust and act on. Without a strategy, tools become noise machines, generating large volumes of findings that overwhelm delivery teams and eventually get ignored. That pattern is common because it is easy to turn on scanners and hard to design the workflow that makes their output meaningful. A good strategy starts with a clear understanding of what each test type is good at, where it fits in the delivery lifecycle, and how findings will be triaged so that effort flows toward the risks that matter most. When the strategy is sound, testing becomes a consistent quality control mechanism that reduces rework and prevents vulnerabilities from reaching production. When the strategy is weak, testing becomes a compliance ritual that drains attention and breeds resentment. The goal here is to build a testing program that is targeted, staged appropriately, and supported by triage rules that reflect real exploitability and business impact. When you do that, tools stop being the center of the conversation and become a support system for better decisions.

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To build that strategy, you need simple, practical definitions of the main test types so teams understand what they are and what they are not. Static Application Security Testing (S A S T) analyzes source code or compiled artifacts to identify patterns that are commonly associated with vulnerabilities, such as unsafe input handling, weak authorization logic, or risky data flows. Dynamic Application Security Testing (D A S T) tests a running application from the outside by sending requests and observing responses, looking for exploitable behaviors such as injection, authentication weaknesses, or unsafe error handling. Software Composition Analysis (S C A) focuses on third-party components and dependencies, identifying known vulnerabilities and licensing risks in libraries, frameworks, and container packages. These definitions are intentionally pragmatic because teams do not need a textbook description; they need to know what kind of signal each tool produces and what kind of work it creates. Each test type sees a different slice of reality: S A S T sees code structure, D A S T sees runtime behavior, and S C A sees dependency exposure. None of them is complete on its own, which is why strategy matters. When teams understand the strengths and blind spots, they stop expecting a tool to answer questions it cannot answer well.

Matching each test type to the stage it fits best is how you keep feedback fast and reduce late surprises. S A S T works best early, close to code changes, because it can run during pull requests or builds and provide feedback while developers still remember what they wrote. It is most useful when it focuses on high-confidence patterns, because early false positives erode trust quickly. D A S T tends to fit later, once an application is deployed into an environment where it can be exercised realistically, because D A S T needs a running target and meaningful authentication context to be effective. It can also be used in continuous monitoring modes, but it still depends on the application being reachable and stable enough for testing. S C A fits throughout the lifecycle, because dependency risk exists whenever dependencies change, but it is especially valuable in the build pipeline where it can block known dangerous versions before they reach production. The stage choice is not only about tool capability; it is about human workflow. Early-stage tools must be fast and precise, while later-stage tools can afford deeper probing because the release boundary is closer and the risk of change is higher. When you align tool type to stage, the program feels supportive rather than disruptive.

Triage is the real heart of testing strategy, because findings only become risk reduction when you decide what to fix first and what to treat differently. Effective triage begins by evaluating exploitability, meaning how likely a finding is to be exploitable in your environment given exposure, control layers, and attacker capabilities. A finding that is theoretically severe can be practically low risk if the vulnerable code path is unreachable, if strong authorization blocks access, or if the system is isolated from untrusted input. Business impact is the second axis, because even a moderately exploitable issue can be high priority if it affects sensitive data, revenue-critical workflows, or privileged operations. Triage also considers ease of remediation and potential for regression, because some fixes are quick and reduce meaningful risk, while others require significant refactoring and should be planned deliberately. The point is not to excuse vulnerabilities; it is to manage effort so teams fix the most important issues reliably rather than failing to fix anything due to overload. Triage should produce clear outcomes, such as fix now, fix soon, mitigate temporarily, or accept with documented rationale, and those outcomes should map to how work gets scheduled. When triage is disciplined, testing output becomes a queue of meaningful work rather than an avalanche.

A common pitfall is treating all findings as equal, which overwhelms teams and destroys the credibility of the testing program. When everything is urgent, nothing is urgent, and developers learn that security findings are an endless stream of demands rather than a prioritized set of risks. This pitfall is often reinforced by dashboards that count findings without distinguishing between exploitability, impact, and confidence. It is also reinforced by policies that mandate remediation of every finding without acknowledging false positives, context, and constraints. The operational result is predictable: teams either ignore findings, create superficial fixes that quiet the tool without improving security, or delay releases until pressure forces exceptions. None of these outcomes is acceptable if the goal is real security improvement. The cure is triage rules that reflect reality and allow focus, paired with sampling to ensure the tools are producing trustworthy signals. When teams see that the program respects their time and targets real risk, they engage. When they see that the program treats every tool output as equally important, they disengage and bypass.

A quick win is creating severity rules that reflect real risk, because good severity rules reduce debate and improve consistency across teams. Severity rules should incorporate exposure, asset criticality, exploit confidence, and control context, such as whether the affected component is internet-facing, handles untrusted input, or runs with elevated privileges. Rules should also incorporate the maturity of the signal, meaning whether the finding is a confirmed exploit path or a pattern match that needs validation. This is where you separate blocking criteria from informational criteria, especially in pipelines where blockers must be rare and high confidence to maintain trust. Severity rules should include time expectations, such as how quickly a critical issue must be addressed, and they should be paired with an exception process for rare cases where remediation cannot happen immediately. The best rules are clear enough that a developer can predict how a finding will be classified and what the next step will be. Predictability reduces friction and prevents constant arguments over priority. When severity reflects real risk, teams spend their energy fixing important issues rather than negotiating labels.

Now consider a scenario where a tool flags hundreds of findings, which is common when tools are introduced to an existing codebase or when a new rule set is enabled. The wrong response is to try to fix everything at once, because that approach often fails and leaves teams demoralized. The better response is to prioritize effectively by first identifying high-confidence, high-impact issues that are likely exploitable in exposed paths. You can then group findings by category to identify common root causes, such as repeated unsafe parsing patterns or repeated missing authorization checks, because fixing a pattern can eliminate many findings at once. Next you establish a baseline, meaning you decide what will be fixed immediately and what will be managed as technical debt through planned work rather than as emergency tasks. In parallel, you validate tool accuracy through sampling, because large volumes often include significant false positives that must be filtered out. You also tune the tool configuration so that it focuses on the paths and patterns that matter most for your environment, because a default configuration is rarely optimal. This scenario is a test of program design, not of developer effort, and handling it well builds credibility quickly. When teams see that the program can prioritize rationally and reduce noise, they are more likely to stay engaged.

Sampling is a practical technique for validating tool accuracy and reducing false positives without requiring exhaustive manual review of every finding. The idea is to take a representative set of findings from each category or severity level and examine them in depth to determine whether they are true positives, false positives, or context-dependent issues. If a category has a high false positive rate, you tune rules or adjust configuration to reduce that noise, because a noisy category will otherwise drain attention indefinitely. Sampling also helps calibrate severity rules, because you can compare what the tool labels as severe with what your environment makes truly risky. Over time, sampling becomes a continuous quality control mechanism for the testing program itself, ensuring that tool updates and new rule sets do not quietly degrade signal quality. It also supports coaching, because sample reviews can be used to teach developers what patterns cause findings and how to fix them correctly. Sampling should be treated as routine maintenance, not as a one-time setup activity, because both codebases and tool behavior change. When sampling is consistent, you keep the signal-to-noise ratio healthy, which is essential for adoption. Tools become useful only when teams trust them, and sampling is one way to earn that trust.

Tracking fix rates and recurrence is how you improve the program over time and avoid the cycle where the same issues return release after release. Fix rate measures how quickly teams resolve findings, especially high-severity ones, and it reveals whether the process is working and whether ownership is clear. Recurrence measures whether issues are being reintroduced, which can indicate weak patterns, missing guardrails, or insufficient training. If recurrence is high, the program should focus on prevention, such as secure coding patterns, reusable components, and pipeline checks that catch the issue early. Tracking also helps you identify where tools are producing low-value output, because categories with low fix rates and high dispute rates often reflect noise or misalignment with reality. Metrics should be used to guide tuning and enablement, not to shame teams, because shame drives hiding and bypass behavior. Fix rate and recurrence also help justify investments, such as improving shared components, training, or adjusting pipeline placements. Over time, these metrics should show that the program is becoming more efficient, with fewer high-risk issues escaping and fewer repeated mistakes. When metrics support learning and improvement, testing becomes part of engineering quality rather than an adversarial demand.

Integrating testing results into backlogs with clear owners is what converts findings into delivered work rather than into reports that no one acts on. Each finding that is accepted for remediation should have an owner, a target timeline based on severity, and enough context that the developer can reproduce and fix it without guessing. Ownership should align with the team that owns the code or the dependency, because security cannot remediate code it does not control. Backlog integration also allows teams to plan work realistically, balancing feature delivery with risk reduction, rather than treating security findings as random interruptions. It is important that backlog items represent validated, triaged findings, because flooding backlogs with untriaged tool output recreates the noise problem in a different system. When integration is done well, developers see security work as part of their normal planning, and leadership can see progress in a way that aligns with delivery tracking. Clear owners also improve accountability, because tasks do not sit in an orphaned state waiting for someone to take responsibility. If you want testing to produce outcomes, backlog integration is the bridge. Without it, the program will remain reporting-heavy and outcome-light.

A memory anchor that ties the strategy together is right test, right stage, right triage, because it prevents the most common program failures. Right test means choosing the tool type that can actually detect the risk you care about, rather than relying on a tool to answer every question. Right stage means placing the test where its feedback is timely and actionable, so fixes are cheap and adoption is high. Right triage means prioritizing by exploitability and business impact so teams focus on meaningful risk reduction rather than drowning in volume. This anchor is useful because it keeps you from treating tooling as the strategy, which is an easy trap. Tools are instruments, but strategy is the system that determines how instruments are used and how their output becomes action. When you repeat this anchor, you also teach teams what to expect, which reduces confusion and increases trust. Over time, the anchor becomes a shared mental model that guides decisions about new tools, new rule sets, and new pipeline placements. A strategy that follows this anchor remains manageable even as the organization scales.

Communicating results in business language is sometimes necessary, especially when leaders need to understand tradeoffs, timelines, and residual risk. Business language does not mean oversimplifying; it means framing findings in terms of impact, exposure, likelihood, and what the organization gains by addressing the issue. For example, rather than describing a vulnerability category, you describe what an attacker could do, such as access sensitive records, disrupt a revenue-critical service, or escalate privileges. You also describe the effort and timeline in terms leaders understand, such as whether the fix is a small change that can ship quickly or a larger refactor that must be planned. Communication should also include the rationale for prioritization, because leadership often sees the largest number on a chart and assumes it is the biggest risk. A clear triage narrative prevents that misunderstanding and helps leaders support the right investments. It is also important to communicate confidence, because some findings are confirmed exploit paths while others are signals that require validation. When leaders understand the signal quality and the impact, they can make better decisions about resourcing and exceptions. Effective communication protects the program from becoming a numbers game.

As a mini-review, keep one strength and one limit in mind for each test type, because that clarity prevents unrealistic expectations. S A S T is strong at catching certain classes of code-level issues early and consistently, especially patterns that map well to static analysis, but it can struggle with context and can produce false positives if rules are too broad. D A S T is strong at finding runtime behaviors that are exploitable through real interfaces, but it depends on having a running target, valid authentication context, and can miss issues that require deep internal state or specific execution paths. S C A is strong at identifying known vulnerabilities in third-party components and providing clear upgrade guidance, but it depends on accurate inventory and can overwhelm teams if transitive dependencies and exploit context are not considered. This mini-review reinforces that each tool sees a different slice of reality and therefore must be used in combination with the others. It also reinforces why triage is essential, because each tool can generate volume that is not equally meaningful. When teams know strengths and limits, they use tools more effectively and trust them more. That trust is what makes the program sustainable.

To conclude, define your triage rules for the next release and treat triage as the operational centerpiece of your testing strategy. Start by agreeing on what factors determine priority, such as exposure, asset criticality, exploitability confidence, and business impact, and then define how those factors map to severities and timelines. Decide which issues will block release, which will be fixed before release without blocking, and which will be scheduled as follow-on work with owners and deadlines. Establish a sampling approach to validate tool accuracy so triage is based on trustworthy signals rather than raw output. Integrate validated findings into backlogs with clear owners, and track fix rates and recurrence so the program improves with each cycle. Finally, keep your strategy anchored on right test, right stage, right triage, because that framework prevents tools from becoming noise machines. When triage rules are clear and consistently applied, teams can focus, delivery remains predictable, and testing becomes a reliable driver of real risk reduction rather than a source of friction and fatigue.

Episode 32 — Build Application Security Testing Strategy: SAST, DAST, SCA, and Triage
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