CVE-2024-30373

Executive Summary

CVE-2024-30373 is a critical remote code execution vulnerability in Kofax Power PDF, specifically within the parsing of JPF files. The flaw is an out-of-bounds write (CWE-787) that occurs when the application fails to properly validate user-supplied data, allowing an attacker to write past the end of an allocated object. Exploitation requires user interaction—the victim must open a malicious JPF file or visit a malicious page. With a CVSS score of 7.8 (High), this vulnerability poses a significant risk to enterprise environments using Kofax Power PDF for document processing. No public proof-of-concept (PoC) or exploit code has been released, and no patch is currently available from the vendor.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It affects a proprietary desktop application (Kofax Power PDF) and is not part of any open-source package registry.

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 opening 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

The high impact across all three security pillars, combined with low attack complexity, makes this a severe threat despite the need for user interaction.

Deep Dive & Mechanics

The vulnerability resides in the JPF file parsing module of Kofax Power PDF. JPF (Java Print File) is a format used for printing and document exchange. The specific flaw is an out-of-bounds write: when parsing a specially crafted JPF file, the application does not validate the size of user-supplied data before writing it to a heap buffer. This allows an attacker to overwrite adjacent memory, potentially corrupting critical data structures or function pointers.

Technical Details:

• Root Cause: Lack of bounds checking on a buffer write operation during JPF parsing.
• Trigger: Opening a malicious JPF file (e.g., via email attachment or web download).
• Impact: Arbitrary code execution in the context of the current user process.
• Exploitability: The vulnerability is exploitable without additional privileges, but requires the victim to interact with the file.

The vulnerability was reported through the Zero Day Initiative (ZDI-CAN-22092), indicating it was responsibly disclosed but remains unpatched.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the CWE-787 description, the vulnerable code likely resembles:

// Vulnerable pseudo-code
void parse_jpf_data(char *input, size_t input_len) {
    char buffer[256];
    // No bounds check
    memcpy(buffer, input, input_len); // Out-of-bounds write if input_len > 256
}

A patched version would include a bounds check:

// Patched pseudo-code
void parse_jpf_data(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 (Offensive)

Prerequisites:

• Kofax Power PDF installed (any version)
• A malicious JPF file crafted to trigger the out-of-bounds write

Exploitation Steps:

1. Craft the Malicious JPF File: Use a fuzzer or manual binary editing to create a JPF file with a large data field that exceeds the expected buffer size.
2. Deliver the File: Send the file via email, a download link, or a compromised website.
3. Trigger the Vulnerability: The victim opens the file in Kofax Power PDF, causing the out-of-bounds write.
4. Achieve Code Execution: Overwrite a function pointer or return address to redirect execution to attacker-controlled shellcode.

Example (Conceptual):

# Python script to generate a malicious JPF file (conceptual)
import struct

# JPF header
header = b'\x25\x50\x44\x46'  # %PDF
# Crafted data to overflow buffer
payload = b'A' * 256 + struct.pack('<I', 0xdeadbeef)  # Overwrite with controlled data
with open('malicious.jpf', 'wb') as f:
    f.write(header + payload)

Note: No public exploit code exists; this is a conceptual example.

Blue Team (Defensive)

Detection:

• Monitor for unusual JPF file activity, especially files with abnormally large sizes or unexpected structures.
• Use endpoint detection and response (EDR) tools to detect heap corruption or out-of-bounds write attempts.

Prevention:

• Restrict execution of Kofax Power PDF in sandboxed environments.
• Implement application whitelisting to prevent untrusted JPF files from being opened.
• Use email filtering to block JPF attachments from unknown senders.

Hunting:

• Search for processes (e.g., PowerPDF.exe) crashing with access violation errors related to heap operations.
• Look for suspicious child processes spawned by Kofax Power PDF.

Indicators of Compromise (IOCs)

• File Hashes: No known malicious samples; monitor for JPF files with unusual sizes (>1MB) or non-standard headers.
• Network Indicators: Outbound connections from PowerPDF.exe to unknown IPs (post-exploitation C2).
• Process Indicators: PowerPDF.exe spawning cmd.exe, powershell.exe, or other shell processes.
• Registry/File System: Unusual DLLs loaded by PowerPDF.exe (e.g., from %TEMP%).

Detection Engineering

YARA Rule

rule CVE_2024_30373_Kofax_JPF_Exploit {
    meta:
        description = "Detects malicious JPF files exploiting CVE-2024-30373"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-30373"
    strings:
        $jpf_header = { 25 50 44 46 }  // %PDF
        $large_data = /.{512,}/        // Data block >512 bytes
    condition:
        $jpf_header at 0 and #large_data > 0
}

Sigma Rule

title: CVE-2024-30373 Kofax Power PDF JPF Exploitation
id: 8a9b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects potential exploitation of CVE-2024-30373 via process anomalies
author: Valters IT
date: 2025-04-01
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\PowerPDF.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\wscript.exe'
            - '\cscript.exe'
    condition: selection
falsepositives:
    - Legitimate use of command line tools by PowerPDF (rare)
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"CVE-2024-30373 Kofax Power PDF JPF Outbound C2"; flow:to_server,established; content:"|25 50 44 46|"; depth:4; content:"|00|"; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Systems: Disconnect any systems running Kofax Power PDF from the network if suspicious activity is detected.
2. Block JPF Files: Use email and web gateways to block JPF attachments and downloads.
3. User Awareness: Train users not to open JPF files from untrusted sources.

Long-Term Fixes:

• Vendor Patch: Await an official patch from Kofax. Monitor their security advisories.
• Alternative Software: Consider using a different PDF reader that is actively maintained and patched.
• Application Hardening: Run Kofax Power PDF in a sandbox or with reduced privileges (e.g., using AppLocker or Windows Defender Application Guard).

Workarounds:

• Disable JPF file association in Windows so that JPF files are not automatically opened with PowerPDF.
• Use file reputation services to scan JPF files before opening.

Valters IT
Securing Digital Frontiers