Deciphering Deception: Using Serial Numbers to Unmask OT Honeypots

In the realm of cybersecurity, honeypots serve as a strategic ploy to entrap attackers, masquerading as legitimate targets. For security analysts, differentiating these decoys from real systems is a critical skill. This article delves into the nuanced art of identifying honeypots by examining serial numbers—a method often overlooked but remarkably telling.

The Role of Serial Numbers in Cybersecurity

Serial numbers are unique identifiers assigned to hardware devices and software instances. In genuine systems, these numbers follow a manufacturer-specific pattern and are rarely duplicated. However, honeypots may betray their true nature through their serial numbers.

Spotting the Signs: Serial Number Analysis

Pattern Recognition: Genuine serial numbers typically exhibit a recognizable pattern or structure. Honeypots, on the other hand, may present serial numbers that are either too random or suspiciously perfect.        

Consistency Checks: Real-world devices from the same batch share similarities in their serial numbers. If a series of devices on a network have identical or non-sequential serial numbers, it could signal a honeypot setup.        

Manufacturer Verification: Serial numbers often contain coded information about the production date and location. Cross-referencing this data with known manufacturer details can expose discrepancies indicative of a honeypot.        

Behavioral Analysis: Interacting with a system can provoke responses that reveal the legitimacy of its serial number. For instance, querying a device for its serial number and receiving a delayed or generic response might suggest it’s a honeypot.        

Practical Application: A Step-by-Step Guide

Gather Data: Use network scanning tools to collect serial numbers from devices across your network.        

Analyze Serials: Employ pattern analysis techniques to evaluate the collected serial numbers for irregularities.        

Cross-Reference: Check the serial numbers against official manufacturer databases when possible.        

Test Responses: Engage with the devices in a controlled manner to observe how they react to specific queries about their serial numbers.        

For example:

Serial numbers are unique to each PLC, meaning that normally multiple PLCs should not have the same serial number. Yet, a Shodan search for this particular serial number, below, reveals that more than 107 connected PLCs have the same one. One can easily deduce that this is a ICS honeypot.

Conclusion

Serial numbers are a gateway to understanding the devices within your network and distinguishing the real from the deceptive. By meticulously analyzing these identifiers, cybersecurity professionals can enhance their threat detection capabilities and focus their efforts on genuine risks.