You bought a smart camera. You want to know what it sends to China. You can't SSH into it. The web interface is secured. The only way in is to open the plastic case and talk directly to the circuit board. Manufacturers often leave "Debug Ports" (UART) open for factory testing. If you find them, you own the device.
The Hardware Lab ($50 Budget)
You don't need an expensive lab. You need:
1. USB-to-TTL Adapter ($5): Usually based on the CP2102 or FTDI chip. Connects your PC USB to the board's serial pins.
2. Logic Analyzer ($15): A cheap Saleae clone is enough to see digital signals and auto-decode protocols.
3. Multimeter: To find Ground (GND) and verify voltage (3.3V vs 5V). Warning: Using 5V on a 3.3V chip will fry it.
1. UART (The Easy Win)
UART (Serial Console) is the most common vulnerability in routers and IoT.
It consists of 4 pins: VCC, GND, TX (Transmit), RX (Receive).
The Attack Plan:
1. Open the device. Look for 4 holes or pins lined up.
2. Use a Multimeter to find GND (continuity test to the metal shielding of the USB/Ethernet port).
3. Turn the device on. Measure the voltage of other pins. The one that fluctuates rapidly is likely TX (it's sending boot logs).
4. Connect your USB-TTL: GND to GND, RX to TX, TX to RX. DO NOT CONNECT VCC (the device is already powered).
5. Open a terminal (Putty/Screen) and guess the Baud Rate (usually 57600 or 115200).
2. SPI Flash Dumping (extracting Firmware)
If UART is password protected, steal the brain.
Locate the SOIC-8 chip (8 legs). This is likely the SPI Flash memory containing the Linux filesystem.
Use a SOP-8 Clip to clamp onto the chip without desoldering it. connect it to a specialized reader (CH341A Minipro).
Run `flashrom` to dump the `.bin` file.
Once you have the bin file, use binwalk to extract the filesystem and look for /etc/shadow to crack the root password.
3. JTAG (God Mode)
JTAG is deeper than UART. It allows you to freeze the CPU, read RAM, and step through instructions.
Identifying Pins: JTAG has many pins (TDI, TDO, TCK, TMS, TRST). They are not always labeled.
Use a JTAGulator or an Arduino with the JTAGEnum sketch to brute-force the pinout.
4. Glitching (Fault Injection)
If the bootloader (U-Boot) is locked ("Press key to interrupt boot" is disabled), you can use Voltage Glitching.
By momentarily shorting the power supply to the CPU (for nanoseconds) at the exact moment it checks the password, you can cause the CPU to skip the check instruction (`JNE` becomes `NOP`).
This requires precise timing (FPGA or ChipWhisperer), but it is undefendable by software.