Silent Drain: From Energy Profiling to Practical Denial-of-Energy Attacks in 5G

In this work, we present Silent Drain, a practical Denial-of-Energy attack against commercial 5G User Equipment (UE). Our approach combines extensive energy profiling across RRC states, DRX cycles, scheduling policies, MCS levels, and MIMO configurations with forged Downlink Control Information (DCI) messages that trigger high-consumption states. In a controlled testbed, we show that periodic DCI replays or forged uplink grants keep the UE in RRC Connected or induce persistent uplink transmissions, maintaining a +1 W power draw and continuous uplink activity for more than 30 minutes even after detachment. We discuss operational feasibility, testbed limitations, and propose potential countermeasures, including physical layer signaling authentication and energy-aware intrusion detection. Our findings reveal that energy efficiency mechanisms can become powerful and predictable attack vectors in 5G.