A Lazy Solve of HHV Challenge 6: Radare2, AVR, & 7-Segment Displays
Ben Gardiner walks through solving HHV Challenge 6, combining Radare2 AVR disassembly, logic analyzer decoding in Sigrok, and 7-segment display reverse engineering.
Summary
Approaching Hardware CTF Challenges Pragmatically
Solving hardware hacking challenges requires chaining disparate skills—from embedded firmware disassembly to digital signal decoding—into a cohesive workflow.
Disassembling AVR Firmware with Radare2
Ben Gardiner demonstrates analyzing an unknown microcontroller firmware dump using Radare2, mapping AVR register operations and interrupt vector tables.
Decoding Digital Signal Traces in Sigrok
Gardiner illustrates using PulseView and Sigrok to capture, inspect, and decode multiplexed GPIO pin toggles driving 7-segment LED displays.
Extracting the Embedded Flag from Display Logic
The walkthrough shows how correlating disassembly control flow with decoded LED pin states recovers the hidden challenge flag.
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