Why CISOs Should Fight Phishing Like a Campaign, Not a Single Email

Jan de Vries · 2026-07-30

If you're a CISO, you already know the feeling. Your inbox is a battlefield, and every day brings a new wave of suspicious messages. But here's the thing: treating each phishing email as a one-off event is exhausting. It's like trying to put out a forest fire one match at a time. That's where campaign-based detection comes in, and it might just be the shift that saves your team's sanity. ### The Real Problem with IOC Fatigue Indicators of compromise (IOCs) are the bread and butter of threat detection. You see a suspicious IP, a weird attachment, or a malicious link, and you block it. But here's the catch: attackers don't send one email and call it a day. They launch campaigns—hundreds, sometimes thousands of messages, all built around a single theme or payload. When you focus on individual IOCs, you're stuck in a reactive loop. Every new email looks like a new problem, and your analysts burn out trying to keep up. That fatigue is dangerous. It leads to missed alerts, slower response times, and a higher chance of something slipping through. The solution isn't to work harder; it's to think smarter. Instead of asking "what is this email?" you should be asking "what is this campaign trying to do?" ### Shifting from Emails to Campaigns Campaign-based phishing detection flips the script. Instead of analyzing each message in isolation, you group them by patterns—common sender domains, similar subject lines, or repeated payloads. This approach gives you a bird's-eye view of the attack. You see the whole picture, not just one pixel. For example, let's say your team spots a fake invoice email. With traditional IOC hunting, you'd block that specific sender and move on. But with campaign detection, you notice the same template is being used across three different domains, all targeting your finance department. Now you're not just blocking one email; you're shutting down an entire operation. That's the kind of visibility that makes a difference. ### Faster Response, Less Noise One of the biggest wins here is speed. When you understand the campaign, you can predict where it's going next. You can preemptively block related domains, update your filters, and alert your users before the next wave hits. This proactive stance cuts your response time dramatically. But it's not just about speed—it's about reducing noise. Analysts spend hours triaging emails that turn out to be variations of the same threat. By grouping them into campaigns, you collapse that workload into a single investigation. One alert, one response, one resolution. Your team can focus on the actual threat instead of drowning in duplicates. ### What This Means for Your Team Think about the morale boost. Your analysts are no longer stuck in a grind of repetitive tasks. They're working on meaningful hunts, connecting dots, and stopping real attacks. That's the kind of work that keeps people engaged and sharp. Here's a quick breakdown of the benefits: - **Better visibility:** You see the full attack surface, not just isolated incidents. - **Accelerated response:** You act on patterns, not single events. - **Reduced fatigue:** Less repetitive triage means less burnout. ### A Practical Starting Point If you're ready to make the switch, start by reviewing your current detection rules. Are they built around individual IOCs? If so, look for ways to group them by behavior. Many modern security tools already offer campaign-based analytics, so you might not need to build anything from scratch. The key is to change your mindset first. As one security veteran put it, "You don't fight a war one bullet at a time. You fight it by understanding the enemy's strategy." The same logic applies to phishing. Stop chasing single emails and start hunting the campaigns behind them. ### The Bottom Line IOC fatigue isn't just a buzzword—it's a real threat to your security posture. By shifting to campaign-based detection, you give your team the tools they need to see the bigger picture, respond faster, and stay sharp. It's not a magic bullet, but it's a significant step forward. And in a world where phishing attacks are only getting more sophisticated, that step could make all the difference.