Illuminated Secrets: Exploiting Display Brightness for Out-of-Band Optical Covert Communication

In recent years, covert communication techniques have gained increased attention due to their potential to bypass traditional security measures. While many existing methods have focused on network-based exfiltration, this paper explores a novel approach that leverages a device's display brightness as an out-of-band optical covert communication channel. By utilizing native system tools such as PowerShell and Windows Management Instrumentation (WMI), we demonstrate how brightness modulation can be exploited to covertly transmit data. This method mimics common visual anomalies, such as screen flickering or cable malfunctions, allowing the data transmission to go unnoticed. Unlike traditional approaches, our technique requires no external plugins or libraries, making it highly adaptable and difficult to detect. Experimental results demonstrate its effectiveness in real-world scenarios, highlighting the method's potential.