There are numerous methods that can be used to attack an IC (integrated circuit).
1. Software attacking
Integrated circuits (ICs) can be vulnerable to software attacks that exploit weaknesses in the processor communication interfaces, protocols, cryptographic algorithms, or security holes in these algorithms. One example of a software attack was the early ATMELAT89C family of microcontrollers, which were targeted by attackers who exploited loopholes in the timing design of the erasing operation. By using a self-designed program, the attacker stopped the next step of erasing the program memory data after erasing the encryption locking bit, making the program non-encrypted and easily read out by a programmer.
Attackers can also use encryption methods to target ICs by developing new attacking devices with software that can execute software attacks. For instance, a device called the Kai Ke Di Technology 51 chip decryption equipment has emerged in China, which can unlock ICs mainly through SyncMos.Winbond by exploiting loopholes in the IC production process. This method involves using programmers to locate inserted bytes, checking whether the chip has a continuous slot (by finding the chip’s continuous FFFF bytes), and then using these bytes to perform the instruction to send the internal program out. Finally, a decryption device is used to intercrypt and obtain the program.
2. electronic detection attacks:
Electronic detection attacks typically involve monitoring the processor’s analog characteristics of power and interface connections during normal operation with high temporal resolution. Attackers can exploit this method by monitoring the microcontroller’s electromagnetic radiation characteristics. As the microcontroller is an active electronic device, its power consumption changes as it executes different instructions. This allows the attacker to obtain critical information in the microcontroller by analyzing and detecting these changes using special electronic measuring instruments and mathematical statistics.
One application of this method is the RF programmer, which can directly read the program of older encryption microcontrollers by using this principle.
3. Error Generation Attack Technology:
Error generation attack technology utilizes abnormal operating conditions to induce processor errors, providing additional access to enable attacks. This technology commonly employs voltage and clock strikes. Low-voltage and high-voltage attacks can disable circuit protection or force the processor to execute incorrect operations. A clock transition can reset protection circuitry without disrupting the protected information. Power and clock transitions can also impact the decoding and execution of a single instruction in some processors.
4. probe technology:
Probe technology involves directly exposing the internal connections of a chip, enabling attackers to observe, manipulate, and interfere with the microcontroller to achieve their attack objectives.
5. UV attack method:
The UV attack method involves applying ultraviolet radiation to a chip, converting it from an encrypted state to a non-encrypted state. Programmers can then directly read the program. This method is particularly useful for one-time programmable (OTP) chips, which can only be erased using UV light. Many OTP chips produced in Taiwan can be decrypted using this method. Half of the OTP chips’ ceramic packages have a quartz window, which can be directly irradiated with ultraviolet light. If the chip is in a plastic package, it must be opened first, and the wafer can then be exposed to ultraviolet light. Because chip encryption using this method is relatively weak, basic decryption does not require significant costs. As a result, the market price of chip decryption is relatively inexpensive. For example, SONIX SN8P2511 and Infineon SCM decryption can be easily accomplished using this method.
6. Chip loopholes:
During the design stage, many chips may have cryptographic vulnerabilities that attackers can exploit to read the code in memory. For instance, in our previous article, we discussed how continuous FF code or special bytes in the search code can be used to reverse-engineer the program in some chips, such as Winbond or Shimao MCU chips, W78E516, N79E825, and AT89C51. Other chips may have more obvious loopholes, such as an encryption pin that becomes ineffective when exposed to electronic signals. Due to the involvement of a Chinese MCU manufacturer in the attack technology, we cannot disclose the specific chip models here. Decryption devices available on the market today generally rely on exploiting chip or program vulnerabilities to achieve IC unlock. However, these approaches may only unlock a limited number of models, and detailed attacking approaches are highly confidential to each lab or company. At Fast PCB Studio, we have developed our own decryption equipment for internal use only. Using specialized approaches and tools, we can reliably unlock chips such as MS9S09AW32, LPC2119LPC2368, and other similar ARM ICs.
7. FIB recovery encryption fuse method:
This technique is applicable to a variety of chips that utilize fuse encryption, with TI’s MSP430 unlocking being the most typical example. Since MSP430 encryption involves burning a fuse, restoring the fuse renders the IC as non-encrypted. This method can be used for various models, such as MSP430F1101A, MSP430F149, MSP430F425, and others. Typically, a probe is used to achieve the fuse re-connection. In the absence of equipment, semiconductor modification companies can modify the lines. The FIB (focused ion beam) equipment or a specialized laser modification equipment can be used to restore the line. However, this approach is not the preferred solution due to the equipment and consumables required, which increases the customers’ cost for IC unlocking work. We will only use this technique if there is no better method available.
8. Modifying the Encryption Circuit:
To bypass the strong encryption of current CPLD and DSP chips, which makes decryption difficult using conventional methods, we need to analyze the chip’s structure and locate the encryption circuit. With the help of specialized equipment, we can modify the chip’s circuitry to make the encryption circuit ineffective. As a result, the previously encrypted DSP or CPLD will become non-encrypted and the codes can be easily retrieved. This technique has been successfully applied to chips such as TMS320LF2407A, TMS320F28335, TMS320F2812, and others.