Extract AVR IC Microcontroller embedded firmware from program memory and data memory, crack AVR MCU tamper resistance system can help to readout MCU code;
Extract AVR IC Microcontroller embedded firmware from program memory and data memory, crack AVR MCU tamper resistance system can help to readout MCU code;
The same test was applied to a chip with a programmed security fuse. the memory gets fully erased before the security fuse is erased. However some security flaws still could exist. Although nothing could be extracted directly by reading the memory when the fuse is erased, power glitch tricks could work. For example, after seven minutes of exposure to the UV light (253 nm peak, 12 mW/cm2) the memory content can be read non-corrupted at VDD below 2.2 V, but the security fuse remains active up to 4.8 V.
If the attacker works out the exact time when the data from memory is latched into the output shift register and the time when the state of the security fuse is checked, he might be able to extract the memory contents by reducing the power supply down to 2 V for the data latching and increasing it to 5 V to make the security fuse inactive.