CVE-2024-5302

Executive Summary

CVE-2024-5302 is a critical out-of-bounds write vulnerability in Kofax Power PDF, a widely used document processing application. The flaw resides in the PDF file parsing engine, where improper validation of user-supplied data allows an attacker to write past the end of an allocated buffer. Successful exploitation requires user interaction (opening a malicious PDF file or visiting a malicious page), and can lead to remote code execution in the context of the current process. With a CVSS score of 7.8, this vulnerability poses a significant risk to enterprise environments relying on Kofax Power PDF for document handling. No public exploit code or patch is currently available, making detection and mitigation critical.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a standalone desktop application (Kofax Power PDF) and does not involve open-source package registries.

CVSS Breakdown & Threat Level

• CVSS Score: 7.8 (High)
• Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Attack Vector: Local (requires user to open a malicious file)
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must open the file)
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: High. The vulnerability allows arbitrary code execution with no privileges required, but user interaction is necessary. Given the lack of a patch, exploitation in targeted attacks is plausible.

Deep Dive & Mechanics

The vulnerability exists in the PDF parsing component of Kofax Power PDF. When processing a specially crafted PDF file, the application fails to validate the size of user-supplied data before writing it to a buffer. This results in an out-of-bounds write, where data is written beyond the allocated memory region.

Root Cause: The parsing logic does not check the length of a specific data field (e.g., a stream or object) against the allocated buffer size. An attacker can craft a PDF with an oversized field, causing a buffer overflow.

Exploitation Path:

1. Attacker creates a malicious PDF file containing a crafted object (e.g., a stream with a manipulated length field).
2. Victim opens the PDF in Kofax Power PDF.
3. The parser reads the crafted data and writes it into a fixed-size buffer without bounds checking.
4. The overflow overwrites adjacent memory, potentially including function pointers or return addresses.
5. The attacker can achieve code execution by controlling the overwritten data.

Impact: Full compromise of the user's session, allowing the attacker to execute arbitrary commands, install malware, or exfiltrate data.

Vulnerable vs. Patched Code

Since no official patch is available, a direct code comparison is not possible. However, the vulnerability is typical of missing bounds checks in C/C++ applications. A patched version would include validation of the data length before writing to the buffer.

Vulnerable Code Pattern (Hypothetical):

void parse_pdf_stream(char *input, size_t input_len) {
    char buffer[256];
    // No bounds check
    memcpy(buffer, input, input_len);
}

Patched Code Pattern (Hypothetical):

void parse_pdf_stream(char *input, size_t input_len) {
    char buffer[256];
    if (input_len > sizeof(buffer)) {
        // Handle error
        return;
    }
    memcpy(buffer, input, input_len);
}

Exploitation & Lab Setup

Red Team (Exploitation)

No public exploit code is available. However, a proof-of-concept can be developed using the following approach:

1. Craft a Malicious PDF: Use a PDF manipulation library (e.g., pdf-parser, peepdf) to create a PDF with an oversized stream object.
2. Trigger the Overflow: Open the PDF in Kofax Power PDF. The overflow will overwrite a critical data structure.
3. Achieve Code Execution: Use techniques like ROP (Return-Oriented Programming) to redirect execution to shellcode.

Example PDF Crafting (Python with pdfminer):

from pdfminer.pdfparser import PDFParser
from pdfminer.pdfdocument import PDFDocument

# Create a malicious PDF with oversized stream
# (Simplified for illustration)
malicious_pdf = b"%PDF-1.4\n1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n3 0 obj\n<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] /Contents 4 0 R >>\nendobj\n4 0 obj\n<< /Length 5000 >>\nstream\n" + b"A" * 5000 + b"\nendstream\nendobj\nxref\n0 5\n0000000000 65535 f \n0000000009 00000 n \n0000000058 00000 n \n0000000115 00000 n \n0000000266 00000 n \ntrailer\n<< /Size 5 /Root 1 0 R >>\nstartxref\n406\n%%EOF"

with open("exploit.pdf", "wb") as f:
    f.write(malicious_pdf)

Usage: Deliver the PDF via phishing email or malicious website. When the victim opens it, the exploit triggers.

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual PDF files with abnormally large stream objects.
• Use endpoint detection and response (EDR) to detect memory corruption events (e.g., access violations, buffer overflow exceptions).
• Deploy network monitoring for PDF file downloads from untrusted sources.

Defense:

• Restrict execution of Kofax Power PDF in sandboxed environments.
• Implement application whitelisting to prevent untrusted PDFs from being opened.
• Use ASLR and DEP to mitigate exploitation.
• Educate users on phishing risks and safe PDF handling.

Indicators of Compromise (IOCs)

• File Hashes (Malicious PDF): (None available publicly; generate upon discovery)
• Network Indicators: Connections to attacker-controlled IPs after exploitation.
• Process Behavior: Kofax Power PDF process (e.g., PowerPDF.exe) exhibiting abnormal memory access patterns.
• Registry/File System: Creation of suspicious files in temporary directories (e.g., %TEMP%).

Detection Engineering

YARA Rule

rule CVE_2024_5302_Kofax_PDF_Overflow {
    meta:
        description = "Detects malicious PDF files exploiting CVE-2024-5302"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-5302"
    strings:
        $pdf_header = "%PDF"
        $stream_keyword = "/Length"
        $large_length = /\/Length\s+[0-9]{4,}/  // Length >= 1000
    condition:
        $pdf_header at 0 and $stream_keyword and #large_length > 0
}

Sigma Rule

title: CVE-2024-5302 Kofax Power PDF Buffer Overflow
id: 8a9b3c2d-1e5f-4a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects potential exploitation of CVE-2024-5302 via abnormal PDF file behavior
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\PowerPDF.exe'
        CommandLine|contains: '.pdf'
    condition: selection
falsepositives:
    - Legitimate PDF files with large streams
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5302 Kofax Power PDF Malicious PDF Download"; flow:to_server,established; content:"%PDF"; http_client_body; pcre:"/\/Length\s+[0-9]{4,}/"; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate: Disable Kofax Power PDF on critical systems until a patch is available.
2. Monitor: Deploy detection rules (YARA, Sigma, Suricata) to identify malicious PDFs.
3. Educate: Train users to avoid opening PDFs from untrusted sources.

Long-Term:

• Apply vendor patch when released.
• Consider alternative PDF readers with better security posture.
• Implement application sandboxing (e.g., Windows Defender Application Guard).

Workaround: Use a PDF previewer or online viewer instead of opening PDFs directly in Kofax Power PDF.

Valters IT