Secured MCU Breaker Experts!

Another simple trick many semiconductor manufacturers use is restricting access to information on memory programming. This is normally used for smartcards, but on some microcontrollers such information is not publicly available as well. This is not a reliable and practical way of making the design secure. Of course it works well with smartcards where all the customers are obliged to sign a non-disclosure agreement with the chip manufacturer. But microcontrollers, with very few exceptions, can be programmed with universal programmers that are widely available from different companies around the world. Even if the programming specification is not documented, all the necessary waveforms can be easily extracted in a few hours with using any low cost oscilloscope, because all the signals are normally applied with less than 1 MHz frequency. If the microcontroller is not supported by a particular universal programmer, it is always possible to buy the development kit directly from the manufacturer and obtain all the necessary protocols from it directly.

We can reverse engineering IC ATMEGA88PV locked flash, please view the IC ATMEGA88PV features for your reference:

When a byte is being programmed into the Flash or EEPROM, reading the address location being programmed will give the value $FF. At the time the device is ready for a new byte, the programmed value will read correctly.
This is used to determine when the next byte can be written.

This will not work for the value $FF so when programming this value, the user will have to wait for at least tWD_PROG_FL before programming the next Flash byte, or tWD_PROG_EE before the next EEPROM byte if Reverse Engineering IC ATMEGA88PV Locked Flash.
As a chip-erased device contains $FF in all locations, programming of addresses that are meant to contain $FF can be skipped. This does not apply if the EEPROM is reprogrammed without chip-erasing the device.

In that case, data polling cannot be used for the value $FF and the user will have to wait at least tWD_PROG_EE before programming the next byte. See Table 30 for tWD_PROG_FL and tWD_PROG_EE values.

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or other conditions beyond those indicated in the operational sections of this specification is not implied when Reverse Engineering IC ATMEGA88PV Locked Flash.

Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Note:
“Max” means the highest value where the pin is guaranteed to be read as low if reverse engineering IC locked flash.
“Min” means the lowest value where the pin is guaranteed to be read as high.
Although each I/O port can sink more than the test conditions (20 mA at VCC = 5V, 10 mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed before reverse engineering IC locked flash:
1] The sum of all IOL, for all ports, should not exceed 100 mA. If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test conditions.
Although each I/O port can source more than the test conditions (3 mA at VCC = 5V, 1.5 mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed when reverse engineering IC locked flash:
1] The sum of all IOH, for all ports, should not exceed 100 mA. If IOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source current greater than the listed test condition if Reverse Engineering IC ATMEGA88PV Locked Flash.

A determined IC attacker could try an easy way to check whether this chip was actually an ASIC. The easy way is to note which pins are connected to power supply, ground, clock, reset, serial, and other interfaces, and to compare all this information with the database of suspect microcontrollers or other mcus. This works very reliably, as each microcontroller family has its own characteristic pinout. Once similarities are found the suspected microcontroller could be verified by placing it into a programming device or universal programmer and trying to read it.

Attack Custom IC which has specific memory structure and system different from standard Microchip, ATMEL microcontroller to extract code from MCU memory, reverse engineering custom IC can help to figure out the internal structure of custom IC;

Attack Custom IC which has specific memory structure and system different from standard Microchip, ATMEL microcontroller to extract code from MCU memory, reverse engineering custom IC can help to figure out the internal structure of custom IC

Semiconductor manufacturers offer valuable customers an easy way to increase the protection of their products: chips with custom marking on the packages instead of standard chip names. That gives the impression that the final product was designed using ASICs or full custom ICs. ‘Everyone knows’ that ASICs offer very good protection against different sorts of attacks and only well equipped and highly skilled attackers could succeed with breaking them. This may stop many potential attackers fiddling with the product.

We can decrypt secured MCU ATMEGA128P code, please view the secured MCU ATMEGA128P features for your reference:
The following charts show typical behavior. These data are characterized but not tested. All current consumption measurements are performed with all I/O pins configured as inputs and with internal pull-ups enabled.

The current consumption is a function of several factors such as: Operating voltage, operating frequency, loading of I/O pins, switching rate of I/O pins, code executed and ambient temperature. The dominating factors are operating voltage and frequency if Decrypt Secured MCU ATMEGA128P Code.

The current drawn from capacitive loaded pins may be estimated (for one pin) as CL·VCC·f where CL = load capacitance, VCC = operating voltage and f = average switching frequency of I/O pin.

The difference between current consumption in Power-down mode with Watchdog Timer enabled and Power-down mode with Watchdog Timer disabled represents the differential current drawn by the Watchdog Timer after Decrypt Secured MCU ATMEGA128P Code.
The ATMEGA128P is a low-power, high-performance CMOS 8-bit microcomputer with 12K bytes of Downloadable Flash codemable and erasable read only memory.

The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout.

The onsecured MCU Downloadable Flash allows the code memory to be recodemed in-system through an SPI serial interface or by a conventional nonvolatile memory codemer before Decrypt Secured MCU ATMEGA128P Code.

Smartcard attack will not be so expensive, because pirate devices are normally based on standard microcontrollers which have much lower security protection than pay-TV smartcards. Very likely the device will be cracked in a few weeks, and the secondary attackers will flood the market with their clones. Fairly soon, the information on how to build pirate devices becomes available on the Internet and anyone can build pirate devices at almost no cost. So the pay-TV service provider loses millions of dollars; sometimes the original attacker is sued or prosecuted. But because the lost profit was distributed among all the pirates and dishonest subscribers, the service provider hardly gets any money back. The only effect of such actions is to threaten the hacker community with punishment. In addition the service provider will have to spend a fortune on redesigning his access control system, choosing and developing software for the new smartcard, and distributing cards to the subscribers

Another example is when the smartcard attacker invests a huge amount of money to reverse engineer a pay-TV access card. Then he disassembles the internal code from the card, learning everything that happens during authorisation and operation. Very likely he would be able to find vulnerabilities which give unlimited access to the subscription channels, for example, by applying a power glitch at just the right moment to cause a malfunction of the CPU. Once he succeeded he could either offer the subscription service at a very competitive price, or sell equipment for counterfeiting the card to malicious people. Obviously such an attacker needs to invest some capital to do this. But once he launches a pirate device on the market, it will be attacked by others.

Anyone who has ever tried to add a modem- or network-card to a PC knows that such an undertaking may produce unwanted results and can take more time than expected. To achieve cost savings from high volume production, the add-in board is designed to be logically compatible to a large variety of motherboards from various vendors. This flexibility makes it necessary to configure the board for its operating environment before it is ready to function. To perform the configuration one needs two pieces of information: sufficient knowledge of the system that the board is expected to reside in and knowledge of the board itself. Once the suitable settings are determined one needs to set jumpers or flip switches on the board. This completes the tricky part of the hardware installation.

We can dump microcontroller ATMEGA128V locked code, please view the microcontroller ATMEGA128V features for your reference:
The ATMEGA128V provides the following standard features: 12K bytes of Downloadable locked code, 256 bytes of RAM, 32 I/O lines, programmable watchdog timer, two Data Pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry.
In addition, the ATMEGA128V is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning if Dump Microcontroller ATMEGA128V Locked Code.
The Power Down Mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset.
The Downloadable locked code can be changed a single byte at a time and is accessible through the SPI serial interface. Holding RESET active forces the SPI bus into a serial programming interface and allows the program memory to be written to or read from unless Lock Bit 2 has been activated after Dump Microcontroller ATMEGA128V Locked Code.

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high impedance inputs. Port 0 can also be configured to be the multiplexed low order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pullups.

Port 0 also receives the code bytes during locked code programming and outputs the code bytes during program verification. External pullups are required during program verification before Dump Microcontroller ATMEGA128V Locked Code.

Port 1 is an 8-bit bidirectional I/O port with internal pullups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.

Some Port 1 pins provide additional functions. P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively after REVERSE ENGINEERING MICROCONTROLLER.

We can recover locked chip ATMEGA128PV binary, please view the locked chip ATMEGA128PV features for your reference:
Port 1 also receives the low-order address bytes during Flash programming and verification.
Port 2
Port 2 is an 8-bit bidirectional I/O port with internal pullups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pullups and can be used as inputs when Recover Locked Chip ATMEGA128PV Binary.
As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR).
In this application, Port 2 uses strong internal pullups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register.
Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.
Port 3
Port 3 is an 8 bit bidirectional I/O port with internal pullups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pullups and can be used as inputs after Recover Locked Chip ATMEGA128PV Binary.
As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups. Port 3 also serves the functions of various special features of the AT89S53, as shown in the following table. Port 3 also receives some control signals for Flash programming and verification.
Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device.
ALE/PROG
Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.
In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory before RECOVER MCU.