Why Advanced Threat Detection Matters: How Kaspersky Helped Uncover a Hidden Breach

Executive Summary

A routine inquiry into email delivery delays turned into a revelation: the client’s environment had been compromised for months. What we uncovered included remnants of a ransomware attack, leaked corporate credentials on dark web forums, and stealthy, unauthorized outbound communication from infected systems. This incident reinforces a critical truth: traditional, signature-based detection is no longer sufficient. Modern threats are low-signal, evasive, and persistent, requiring tools that combine real-time telemetry, behavioural analysis, and contextual intelligence.

From Email Complaints to Hidden Malware

A mid-sized client reported issues with outbound emails. But beneath the surface, our investigation exposed far more serious concerns:

• Misconfigured email security protocols (SPF, DKIM, DMARC), which enabled spoofing and impersonation of executive level personnel
• Evidence of phishing attempts likely designed to deceive internal staff
• A ransomware incident from months prior thought to be contained, but never fully eradicated

To validate our concerns, we initiated a compromise assessment using our Endpoint Detection and Response (EDR) platform powered by Kaspersky.

The Turning Point: Suspicious Web Activity

During the assessment, Kaspersky flagged a suspicious outbound connection from one endpoint:

"https://routerpp[.]life/api/v1/product-visits"

At face value, the domain appeared harmless, resembling standard product tracking or analytics. But Kaspersky’s Web Threat Protection blocked the request in real time and identified it as malicious.

Here’s why it stood out:

• The site used Russian-language gambling content to disguise malicious traffic
• It communicated using API-style requests, simulating legitimate web activity
• The traffic originated from a Chrome browser process, blending into normal behavior
• All communication was encrypted using modern TLS protocols

While only 3 out of 97 security vendors detected it as malicious; Kaspersky, CyRadar, and SecLookup, most others returned a clean verdict.

What We Uncovered Next

That single alert triggered a broader investigation, which revealed:

• Leaked staff credentials circulating on underground markets
• Unpatched critical vulnerabilities in public-facing infrastructure
• Persistence mechanisms on compromised endpoints including suspicious scheduled tasks and registry entries
• Indicators that the compromise dated back to the earlier ransomware attack with attackers likely never having left

This was not an isolated event. It was a long-term breach, potentially resold by Initial Access Brokers (IABs) to other threat actors, including ransomware affiliates.

Why Most Security Tools Missed It

The domain was submitted to a well-known multi-engine scanner. The results?

• Malicious verdicts: Only 3 vendors
• Clean verdicts: Over 90

Why the gap?

1. Traffic looked legitimate: It mimicked browser-based API requests over HTTPS
2. No obvious malware payload: Static scanners had no indicators to work with
3. Recently created domain: Lacked enough history to trigger reputation-based alerts
4. Encrypted communications: Made inspection difficult without process-level context

This highlights the limitations of traditional detection methods especially when adversaries are using stealth, encryption, and legitimate tools to evade detection.

Why Kaspersky Detected What Others Missed

Kaspersky’s advanced detection capabilities offered unique visibility into this threat:

This wasn’t a typical malware dropper. It was stealthy, encrypted, and persistent and without an intelligent EDR, it would have gone completely undetected.

Key Takeaways for Security Leaders

1. Don’t trust the majority: If 94 vendors say “clean,” it doesn’t mean you’re safe
2. EDR is essential: Especially when you’re dealing with an already compromised environment
3. Commodity malware is evolving: RedLine, Vidar, and similar tools now mimic legitimate user behavior
4. Outbound detection matters: Attackers don’t just get in, they talk out
5. Don’t stop at ransomware: Often it’s just the final stage of a much longer campaign

Final Thoughts

This incident makes one thing crystal clear: attackers are getting smarter, stealthier, and quieter. And if your defenses aren’t built to see what’s hiding in plain sight, you may already be compromised. Kaspersky’s role in this case wasn’t just to block a threat. It helped illuminate an entire attack chain that most security tools missed. That’s the kind of visibility modern organizations need, not just to react, but to stay ahead. If your current tools aren’t giving you this level of insight, it’s time to ask the hard question: “What am I not seeing?”