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Introduction: The Persistent Danger of Default Credentials
Despite years of security awareness campaigns, default passwords remain one of the easiest entry points for cybercriminals. This vulnerability isn’t just a beginner’s mistake — it’s a systemic oversight repeated across industries, networks, and personal devices. In this hands-on exploration, cybersecurity intern Matthew Paul reveals just how effortless it still is to exploit unprotected systems. Using advanced tools like Malcolm, Arkime, and Zeek, he dives deep into real-world data to uncover the anatomy of an attack. His findings offer a wake-up call to IT admins, businesses, and security professionals: if you haven’t changed your default credentials, you’re practically begging to be hacked.
Advanced Honeypot Deployment and Real-World Intrusion
Matthew Paul, participating in the SANS.edu BACS program, set up an advanced honeypot as part of his internship with the SANS Internet Storm Center. Rather than relying solely on log-based analysis, he opted for a packet-focused approach, installing Malcolm — an open-source network security monitoring and intrusion detection system (NSM/IDS) — on a bare-metal Intel NUC. Malcolm integrates a wide suite of powerful tools like Zeek, Suricata, Yara, ClamAV, and Arkime to provide a comprehensive traffic analysis environment. To monitor traffic, Paul configured a 5-port managed switch with a mirrored port to route all honeypot traffic to the Malcolm sensor.
He also explored the optional integration of Hedgehog Linux, which could act as a PCAP ingestion sensor to further offload analysis tasks. Though he didn’t deploy Hedgehog, he outlined its value for scaling setups and improving capture efficiency. Malcolm’s flexibility in deployment — whether as an ISO or via containerized environments — made it ideal for this project, especially given the robust documentation and community support available at malcolm.fyi.
After successful setup, he analyzed logs, particularly focusing on Zeek’s Weird Logs, which highlight protocol anomalies. In one incident, filtering for Telnet sessions revealed malicious traffic from a Russian IP using default UNIX credentials like jvbzd, a password flagged by SANS as insecure back in 2016. The session was unencrypted, making it easy to capture and examine using tools like Arkime and Wireshark. Attackers attempted recon commands like mount and used utilities such as wget in a failed attempt to gain further control. The threat actor, thwarted by the honeypot’s containment, eventually abandoned the attempt.
This entire sequence — from initial packet capture to forensic analysis — underscores how easily attackers exploit systems using factory-set credentials. It also highlights how powerful Malcolm is as a defensive tool, making packet-based analysis approachable and efficient for security teams.
What Undercode Say:
The Ongoing Security Nightmare of Default Passwords
Default passwords are not just a rookie oversight — they represent a glaring weakness that persists across both consumer and enterprise environments. What Matthew Paul’s experience reinforces is that even in 2025, attackers are still actively exploiting devices with unchanged credentials. This issue is magnified in Internet of Things (IoT) devices, routers, industrial systems, and outdated legacy software that rely on hardcoded logins for initial access.
Malcolm as a Force Multiplier in Threat Detection
The real hero of this diary is Malcolm, a remarkably powerful yet underused tool in the cybersecurity landscape. Its ability to combine tools like Zeek, Arkime, and Suricata under one umbrella gives defenders a holistic view of threats in real time. Packet-level analysis, while traditionally more demanding, becomes digestible through Malcolm’s dashboards and visualization tools. The integration of protocol-specific anomaly detection, especially for ICS/SCADA networks, gives it a unique edge over generic intrusion detection systems.
Telnet and the Echoes of Poor Security Hygiene
The attack Matthew traced came through Telnet — an insecure, outdated protocol that should be long retired from any modern environment. Its presence in real-world attacks shows a staggering amount of neglected system hygiene. Even worse is the success of default password brute-forcing, which means systems are being deployed and left exposed without proper configuration. These are preventable threats with well-known solutions.
Layered Detection Pays Off
Paul’s use of Zeek’s Weird Logs to identify protocol anomalies is a tactic not often employed by beginners. It’s a brilliant example of layered detection strategies. Most defenders might overlook such logs, but anomalies like null bytes in communication (“) offer rich signals of intrusion attempts. His workflow — from anomaly detection to IP identification to full PCAP analysis — should be part of every SOC playbook.
The Value of Manual Analysis
Automated alerts are valuable, but Paul’s method emphasizes the irreplaceable power of human-driven, context-aware investigation. He used visual tools to filter traffic by protocol, examined attack patterns by country, and traced threat actor behavior over time. This is threat hunting in its truest form — proactive, deliberate, and insight-rich.
Education That Matters
Internships like this one offer a glimpse into the real value of experiential learning in cybersecurity. Instead of relying on abstract case studies, students like Paul are thrown into real-world network conditions, dealing with live data, threat actors, and operational challenges. His success story is also a testament to the structure and support of programs like SANS.edu BACS.
Why This Matters in 2025
We are in an era where nation-states and criminal groups automate reconnaissance at a massive scale. A single unpatched, misconfigured device can become a beachhead for broader attacks. This article isn’t just a technical walkthrough — it’s a call to arms. Whether you’re a home user or an enterprise IT admin, changing default credentials must be step one in any cybersecurity plan.
Don’t Just Deploy — Harden
Too many teams focus on getting systems online quickly, assuming they’ll circle back to secure them later. But attackers move fast, often scanning and exploiting devices within minutes of being publicly accessible. Default credentials aren’t just bad practice; they’re a neon sign to attackers saying, “This one’s easy.”
What This Diary Really Teaches
It teaches the discipline of deep monitoring, the elegance of packet-based insight, and most importantly — that cyber defense doesn’t need to be expensive or overly complex. Free, open-source tools like Malcolm, when configured correctly, can reveal everything from casual probes to serious breaches. And it all starts with rejecting laziness in setup — especially when it comes to credentials.
🔍 Fact Checker Results:
✅ Default passwords remain widely exploited in 2025, especially in Telnet and IoT devices.
✅ Malcolm is an actively maintained, legitimate tool supported by CISA and the infosec community.
❌ Hedgehog Linux is not required to run Malcolm, although it enhances its capabilities.
📊 Prediction:
Expect a rising wave of automated attacks targeting devices left with default or hardcoded passwords, especially in smart homes and industrial networks. Cyber hygiene, particularly basic practices like changing default logins, will become a top priority in cyber policy enforcement across sectors. The tools may evolve — but the vulnerabilities stay the same. 🛡️🔐
References:
Reported By: isc.sans.edu
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