Security teams are under constant pressure to do more with less. Budgets rarely keep pace with the explosion of threats, while the complexity of modern IT environments continues to grow. SOC leaders invest heavily in SIEMs, EDRs, and threat intelligence feeds, confident they’ve built a program that can stand up to attackers.
But beneath the dashboards, metrics, and daily alerts, there’s a problem that rarely gets the attention it deserves: detection gaps.
These blind spots exist inside every SOC, regardless of size or maturity. They’re the silent threat that undermines detection coverage, erodes trust in the SOC, and leaves organizations exposed to adversaries who rely on these very weaknesses to succeed.
The Illusion of Coverage
On paper, most SOCs look strong. Telemetry is flowing in from endpoints, cloud services, and network devices. Detection rules are written. Dashboards are green. Analysts are closing alerts daily.
But then a red team engagement (or worse, a real breach) reveals the uncomfortable truth: entire categories of adversary behavior were never detected.
This is the illusion of coverage. Just because data exists doesn’t mean it’s being analyzed in your SIEM. Just because you have rules deployed doesn’t mean they’re effective. And just because alerts are firing doesn’t mean you’re covering the techniques attackers are actually using today.
The reality: attackers thrive in the spaces you’re not monitoring. And most organizations don’t know where those spaces are.
Why Detection Gaps Happen
Detection gaps are not the result of negligence. They’re the natural outcome of how SOCs operate. Let’s look at three common causes:
Rule Decay
Detection rules have a lifecycle. They’re written, tested, deployed, and then often forgotten. Adversaries evolve, new log sources appear, and environments change. Without active maintenance, rules decay. Over time, they fail to capture relevant activity, or they stop firing altogether.
Example: A rule designed to detect certain usage of PowerShell looks for powershell.exe. But with PowerShell’s version 6 update, the new process name is pwsh.exe pwsh.exe. The original rule does not account for this updated process name, so it silently fails to detect potentially malicious activity.
Incomplete Mapping
Even well-staffed SOCs struggle to cover an adequate amount of the MITRE ATT&CK framework. There are more than 200 techniques and sub-techniques and only so many hours in the day. As a result, many SOCs focus narrowly on the most obvious techniques, leaving large portions of the kill chain invisible.
Example: An organization may have strong detections for privilege escalation on Windows endpoints but no coverage for cloud-specific persistence methods like AWS IAM role modifications. For a company that has shifted workloads to the cloud, this is a critical blind spot.
Operational Drift
Change is constant inside the SOC. SIEM migrations, cloud adoption, and integrations with new security tools create complexity. Rule tuning meant to reduce false positives often removes valuable signal. Analysts churn out of roles, taking institutional knowledge with them. Over time, these changes create drift between the SOC’s intent (what it thinks it’s monitoring) and reality (what’s actually covered).
The result is a growing set of blind spots that attackers can exploit at will.
The Cost of Detection Gaps
Detection gaps create a false sense of security. Executives see metrics showing thousands of alerts processed and assume the SOC is effective. In reality, adversaries may be operating freely in areas no one is watching.
The cost of these blind spots includes:
- Delayed detection: Attacks are identified only after damage is done.
- Inefficient investigations: Analysts chase noise while critical activity goes unseen.
- Wasted investment: Millions are spent on SIEMs and XDRs that aren’t delivering the coverage expected.
- Direct financial costs: detection blind spots add significant breach risk, leading to ransom payments, regulatory fines, legal fees, and customer churn
- Reputational damage: When breaches occur, stakeholders lose trust in the SOC’s ability to defend the business.
The harsh truth: you can’t defend what you can’t detect.
From Alert Chasing to Threat-Informed Detection Engineering
Closing detection gaps requires a fundamental shift in mindset. Traditional SOCs are built around alert handling: investigate, escalate, close. While necessary, this reactive cycle does nothing to improve long-term coverage.
Forward-looking organizations are adopting threat-informed detection engineering—a discipline focused on proactively designing, validating, and maintaining detection content to detect adversary tactics, techniques, and behavior.
Detection engineering in this style takes a preemptive approach and aims to “shift left” of the alert itself to ensure that detections are built on attacker intent, and not just syntax or isolated signals. Instead of waiting for gaps to reveal themselves during an incident, detection engineers continuously assess coverage and close blind spots before adversaries exploit them.
Best Practices for Closing Detection Gaps
Leading SOCs are making progress by embracing the following practices:
Map Detections to MITRE ATT&CK
The ATT&CK framework has become the industry standard for understanding adversary behavior. By mapping detection rules to ATT&CK techniques, SOCs can see exactly which adversary TTPs are covered and which are not. This transforms coverage from guesswork into measurable fact.
Validate Rule Effectiveness
It’s not enough to know a rule exists—it must be tested. Continuous rule validation ensures that detections work as intended and have not become “broken” or ineffective over time.
Prioritize High-Impact Techniques
Not all ATT&CK techniques are equal. SOCs should focus engineering efforts on the techniques most relevant to their environment and threat model. For example, a financial institution may prioritize credential dumping, while a SaaS company may focus on cloud persistence methods. Operationalizing your threat intelligence can go a long way in narrowing down the long list of potential detections to the select few techniques that adversaries are actively using to target organizations similar to yours.
Add Coverage with New Detections
Once you’ve identified your top priorities for eliminating coverage gaps – such as specific APT groups, Tactics and Techniques, or log source types – you need a process to consistently add new rules that help to add coverage for the threats most relevant to your organization. Developing an effective detection engineering workflow is key for any SOC team but this can also be automated through a platform for increased accuracy and speed.
The Human Side of Detection Engineering
Detection engineering is not just about tools and frameworks. It’s about people. SOC analysts who once focused only on alert triage now have opportunities to build and refine the very rules that protect the business – this is a mindset shift to focus on treating the cause, not the symptom.
This shift elevates the SOC from a reactive function to a strategic defender. Analysts gain new skills, career paths open, and the work becomes more engaging. At a time when burnout and turnover are high, investing in detection engineering can also be a retention strategy.
Measuring What Matters
Traditional SOC metrics—mean time to detect (MTTD), mean time to respond (MTTR), or number of alerts investigated—offer limited insight into actual security effectiveness. They measure activity, not coverage.
Instead, SOCs should focus on coverage metrics:
- Percentage of relevant ATT&CK techniques covered
- Effectiveness of detections (rules that fire correctly vs. those that don’t)
- Trend of coverage over time (gaps shrinking or growing)
Coverage metrics provide executives with a clear answer to the most important question: Do we have visibility into the threats that matter most to our business?
Conclusion: Turning Blind Spots Into Strengths
Detection gaps are the silent threat that weaken even the best SOCs. They thrive in assumptions, complexity, and drift. Left unchecked, they leave organizations vulnerable to the very attacks they believe they’re prepared to stop.
But these gaps are not permanent. By adopting threat-informed detection engineering practices—mapping coverage, validating rules, prioritizing high-impact techniques, and measuring what matters—SOCs can transform blind spots into strengths.
The result: a SOC that doesn’t just chase alerts, but actively builds resilience. One that provides executives with confidence. And most importantly, one that keeps attackers from operating in the shadows.