3 Key Takeaways
- Security and fraud controls decay over time—especially when facing smart, persistent human adversaries who adapt faster than your processes do.
- Mapping the criminal business process helps build typologies, essential for designing detection logic to embed into your fraud, insider threat, and SIEM systems.
- You must monitor control decay continuously using early indicators and adaptive analytics—not just wait for losses or incidents to show you’ve failed.
The Adversarial Evolution Challenge
Fraud and security controls face a unique challenge: they’re not defending against random failures or faulty processes—they’re up against people. Adaptive, intelligent, persistent people.
Think of it like this: you lock your doors. But if someone really wants in and watches you long enough, they’ll figure out where the spare key is. That’s what control decay looks like when your adversary is watching, learning, and evolving. Over time, even the best-designed controls wear thin against determined adversaries—especially when those adversaries have motivation, time, and community support.
This constant pressure creates a cycle where:
- Controls lose effectiveness as attackers discover workarounds.
- Fraudsters evolve their TTPs (tactics, techniques, and procedures) to sidestep your latest defences.
- Control bypass techniques get shared in underground forums, speeding up the learning curve for others.
- Every successful breach becomes a repeatable blueprint—one your analytics may not be trained to detect.
The Real Cost of Ignoring Control Decay
In 2023, reported global losses from fraud hit US$485 billion, with insider threat incidents costing an average of US$16.2 million each. And those figures only capture what’s been detected and disclosed.
Control decay is especially dangerous in environments that depend on digital platforms (e.g. eCommerce, online banking), protecting trade secrets, and product protection. Supply chains and distirbution are particularly vulnerable. Third parties may have weaker controls, creating backdoors into your systems. And when fraud or insider threats go unnoticed, they erode trust and value, fast.

From Static to Smart: Rethinking Controls
Many organisations treat security and fraud controls as one-time investments—set them, test them, and move on. That mindset doesn’t work against adaptive human threats.
Controls decay like milk, not wine. Even when controls are automated, humans are still involved—approving actions, ignoring alerts, or skipping procedures. Over time, fatigue and complacency creep in, creating gaps that adversaries can exploit. That’s why it’s essential to continuously reassess the effectiveness of your defences, a process known as ‘control assurance’.
Mapping the Criminal Business Process
Before you can improve detection, you need to understand the steps an adversary must take to succeed. That’s where mapping the criminal business process comes in.
This means reverse-engineering the steps an adversary would take to achieve their goal—whether that’s stealing research data, committing payment fraud, or accessing protected systems. By mapping out their “workflow,” you can identify where to disrupt them.
Key disruption opportunities include:
- Reconnaissance – How do they learn about your systems, people, or gaps?
- Access – What path do they use to gain entry (e.g., phishing, credential reuse)?
- Evasion – How do they stay under the radar?
- Monetisation – What do they do with what they’ve taken?
- Exit strategy – How do they cover their tracks?
This process forms the backbone for building targeted detection strategies.
Typologies: Turning Adversary Tactics into Detection Models
Once you understand the criminal business process, you can develop typologies. These are structured descriptions of how specific threats play out in your context—complete with behavioural indicators, red flags, and contextual cues.
Typologies aren’t just lists of “bad behaviours.” They are comprehensive models that describe how specific threats manifest within a particular context. A typology outlines the sequence of actions, behavioural indicators, contextual factors, and potential red flags associated with a particular threat scenario:
- They aggregate indicators, sequences, and behaviours that point to fraud or compromise.
- They include the context—industry, access levels, timing—that makes them relevant.
- They support prioritised detection by translating threats into models your systems can monitor.
Developing typologies involves analyzing real-world cases to identify common patterns and methods used by adversaries. One effective approach is Comparative Case Analysis (CCA), which compares multiple incidents to extract shared characteristics and inform the development of robust typologies.
From Typologies to Detection: Using Analytics to Catch Adaptation
Once established, these typologies serve as the foundation for designing analytics-based detection models. By translating the insights from typologies into detection logic, organizations can proactively monitor for activities that align with known threat patterns, enabling earlier identification and response to potential incidents.
Data analytics helps you identify these early signs of attacker adaptation—well before a control fails outright. By building detection around these patterns, you shift from reactive incident response to proactive defence.
- Anomaly Detection – Spot subtle changes in normal activity before a bypass is successful.
- Clustering & Pattern Discovery – Uncover organised campaigns or repeated techniques across cases.
- Temporal & Spatial Analysis – Track when and where new threats emerge or evolve.
- Simulations & Wargaming – Test how your controls stand up to evolving TTPs (modus operandi) in different organisational contexts or business processes (inclusive of internal control points).
- Threat Intelligence Integration – Correlate public vulnerabilities or attack trends with what’s happening in your own data.
Measuring and Monitoring Control Decay
You can’t improve what you’re not measuring. Most businesses track breaches and incidents—but that’s too late. Control decay needs earlier signals.
The goal is to monitor signs that controls are being weakened, tested, or circumvented—even if the attacker hasn’t succeeded yet. These metrics give you early warning that your system is becoming vulnerable.
- Bypass Detection Rate – How often are adversaries getting around your controls?
- Control Learning Curve – How fast are attackers adapting after implementation?
- Adaptation Indicators – Are there new methods or patterns in failed attempts?
- Control Evasion Techniques – What are the latest tricks being used to slip past detection?
- TTP Evolution Tracking – How are known techniques changing over time?
- Reconnaissance Patterns – Is someone repeatedly probing or testing your systems?
- “Low and Slow” Attacks – Are there stealthy signs of gradual testing or exploitation?
- Correlation with Vulnerability Disclosures – Do public CVEs line up with spikes in suspicious activity?

Countering Control Decay with Adaptive Analytics
Now that you’re watching for decay, you need to build controls that respond to it. Static rules can’t keep up with adversaries that are constantly learning and evolving.
This is where adaptive analytics come in. By layering behavioural insights, detection flexibility, and external intelligence, you can keep your controls sharp and responsive.
- Control Variation – Don’t apply identical rules across environments—vary thresholds and triggers to make it harder to game the system.
- Adaptive Rule Sets – Let your system adjust thresholds when probing is detected.
- Behavioural Baselines – Define “normal” for each user or system, and refresh those profiles regularly.
- Interdependent Control Effectiveness – Evaluate how your layers of control interact—do they actually reinforce each other?
- Simulate Responses – Use testing and wargames to anticipate how controls would respond to emerging tactics.
- Threat Intelligence Integration – Don’t just collect external threat data—use it to shape detection models and control tuning in real time.
TL;DR: The Threat Is Human, and So Is the Weakness
Your adversaries are human, which means they’re persistent, curious, and adaptive. They’ll keep pushing until they find a way through.
But the people inside your organisation—who operate, review, and respond to controls—are also human. And humans get bored, distracted, and desensitised. That’s how control decay happens, both technically and culturally.
The big mistake is waiting for a loss to act. Losses are lagging indicators—they tell you your controls already failed. The real win is spotting decay before the breach. That means checking your data constantly for signs that someone’s testing your system or that your team has stopped paying attention.
Wondering what to do next? Start by looking at your risks and controls, and doing some data analytics on key processes, products or information against historical incidents and near misses to understand what’s going on. Then identify indicators of control decay, and build dashboards to monitor the. And don’t forget to look at them regularly!
Further Reading:
- Coole, R., & Brooks, R. (2009). Security Decay: An entropic approach to definition and understanding. Proceedings of the 2009 International Conference on Security and Management (SAM).
- Curwell, P. (2023). Comparative Case Analysis: A powerful tool for typology development
- Curwell, P. (2022). Alert management and insider risk continuous monitoring systems
- Curwell, P. (2022). “Typologies” Sound Boring – But They Could Save Your Business Millions
- PMC (PubMed Central). (2022). Cyber risk and cybersecurity: a systematic review of data availability. Frontiers in Cybersecurity, 4, 823456. https://doi.org/10.3389/fcose.2022.823456
- Oxford Academic. (2020). Decomposition and sequential-AND analysis of known cyber-attacks on industrial control systems. Journal of Cybersecurity, 6(1). https://doi.org/10.1093/cybsec/tyaa009
- ScienceDirect. (2021). Control-theory based security control of cyber-physical power systems. ISA Transactions, 109, 1-12. https://doi.org/10.1016/j.isatra.2020.10.008
- South African National Treasury. (2015). Risk Appetite and Risk Tolerance – Making sense of it in the public sector. Retrieved from http://www.treasury.gov.za/
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