CVE-2025-14418

Executive Summary

CVE-2025-14418 is a remote code execution vulnerability in pdfforge PDF Architect, specifically within the processing of XLS files. The flaw arises from insufficient UI warnings when dangerous script content is embedded in an XLS file, allowing an attacker to execute arbitrary code in the context of the current user. The vulnerability requires user interaction—the victim must open a malicious XLS file or visit a malicious page that triggers the file download. With a CVSS score of 7.0 (High), this poses a significant risk to end-user workstations, especially in environments where PDF Architect is used for document conversion or editing. No public exploit code or patch is currently available, and the EPSS score is 0.0%, indicating low exploitation activity at this time.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It affects a proprietary desktop application (pdfforge PDF Architect) distributed via the vendor’s website or third-party download sites. Users should verify the integrity of downloaded installer files using checksums provided by the vendor.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Local (L) – The attacker must deliver the malicious file to the victim.
• Attack Complexity (AC): Low (L) – No special conditions required beyond user opening the file.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – Victim must open the malicious XLS file.
• Scope (S): Unchanged (U) – The vulnerability does not cross trust boundaries.
• Confidentiality (C): High (H) – Full data access possible.
• Integrity (I): High (H) – Arbitrary code execution allows data modification.
• Availability (A): High (H) – Code execution can disrupt system availability.

Threat Level: High – Exploitation requires user interaction but can lead to full compromise of the user’s session.

Deep Dive & Mechanics

The vulnerability resides in the XLS file parsing module of pdfforge PDF Architect. When the application opens an XLS file, it fails to properly warn the user about embedded macros or dangerous script content (e.g., VBA macros, DDE commands, or Excel 4.0 macros). The application likely uses a library or custom code to parse XLS files, but it does not implement a security prompt or sandboxing for script execution. As a result, an attacker can craft an XLS file containing malicious script that executes automatically upon opening, without the user being warned.

The specific flaw (ZDI-CAN-27502) indicates that the issue was reported through the Zero Day Initiative, suggesting it was responsibly disclosed. However, the patch status is unknown, meaning the vendor may not have released a fix.

Attack Flow:

1. Attacker creates a malicious XLS file with embedded script (e.g., VBA macro that downloads and executes a payload).
2. Attacker hosts the file on a website or sends it via email.
3. Victim opens the XLS file in PDF Architect (e.g., via drag-and-drop or file open dialog).
4. PDF Architect processes the file without displaying a security warning.
5. The embedded script executes in the context of the current user, allowing code execution.

Vulnerable vs. Patched Code

Since no patch is available, a comparison cannot be made. However, a secure implementation would include:

• A warning dialog before executing any script content in XLS files.
• Disabling script execution by default, requiring explicit user consent.
• Sandboxing the script execution environment.

Vulnerable Code (Conceptual):

// Vulnerable: No UI warning before executing script
void ProcessXLS(string filePath) {
    var workbook = OpenXLS(filePath);
    ExecuteMacros(workbook); // No user prompt
}

Patched Code (Conceptual):

// Patched: Prompt user before executing macros
void ProcessXLS(string filePath) {
    var workbook = OpenXLS(filePath);
    if (workbook.HasMacros) {
        var result = MessageBox.Show("This file contains macros. Execute?", "Security Warning", MessageBoxButtons.YesNo);
        if (result == DialogResult.Yes) {
            ExecuteMacros(workbook);
        }
    }
}

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Windows 10/11 VM with pdfforge PDF Architect installed (any version).
• Attacker machine with a web server or email client.
• Tools: Metasploit, Cobalt Strike, or custom VBA payload generator.

Exploitation Steps:

1. Generate a malicious XLS file with an embedded VBA macro that executes a reverse shell or downloads a payload.

   Sub Auto_Open()
       Dim objShell As Object
       Set objShell = CreateObject("Wscript.Shell")
       objShell.Run "powershell -NoP -NonI -W Hidden -Exec Bypass -Enc <base64_encoded_payload>"
   End Sub
   

2. Save the file as malicious.xls.
3. Host the file on a web server or send it via email.
4. When the victim opens the file in PDF Architect, the macro executes automatically (no warning).
5. The payload runs, establishing a reverse shell or executing arbitrary commands.

Note: No public exploit code is available; this is a conceptual demonstration.

Blue Team (Defensive)

Detection:

• Monitor for PDF Architect processes spawning child processes (e.g., cmd.exe, powershell.exe).
• Enable Windows Defender Attack Surface Reduction (ASR) rules to block Office macro execution from untrusted sources.
• Use Sysmon to log process creation events (Event ID 1) and network connections (Event ID 3).

Hunting:

• Search for XLS files opened by PDF Architect that contain macros (use YARA rule below).
• Look for anomalous child processes of PDFArchitect.exe (e.g., powershell.exe, wscript.exe).

Indicators of Compromise (IOCs)

• File Hashes: (None available; placeholder)
  • malicious.xls: SHA256 e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Indicators:
  • Outbound connections to attacker-controlled IPs/domains from the victim machine.
• Process Indicators:
  • PDFArchitect.exe spawning cmd.exe, powershell.exe, or wscript.exe.
• Registry Indicators:
  • Persistence mechanisms added by the payload (e.g., HKCU\Software\Microsoft\Windows\CurrentVersion\Run).

Detection Engineering

YARA Rule

rule CVE_2025_14418_XLS_Macro_Detection {
    meta:
        description = "Detects XLS files with embedded macros targeting CVE-2025-14418"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-14418"
    strings:
        $macro_indicator = "Auto_Open" nocase
        $vba_signature = "VBA" nocase
        $ole2 = { D0 CF 11 E0 A1 B1 1A E1 }  // OLE2 magic bytes
    condition:
        $ole2 at 0 and $vba_signature and $macro_indicator
}

Sigma Rule

title: Suspicious Child Process from PDF Architect
id: 7a8b3c4d-5e6f-7890-abcd-ef1234567890
status: experimental
description: Detects PDF Architect spawning a shell or script interpreter, potential exploitation of CVE-2025-14418
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\PDFArchitect.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\wscript.exe'
            - '\cscript.exe'
    condition: selection
falsepositives:
    - Legitimate use of PDF Architect with external tools (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-14418 - Potential XLS Macro Download"; flow:to_server,established; content:"Content-Type|3a 20|application/vnd.ms-excel"; nocase; content:".xls"; nocase; pcre:"/Auto_Open/i"; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

1. Vendor Patch: Await an official patch from pdfforge. Monitor the vendor’s website or ZDI advisory for updates.
2. Disable Macro Execution: If possible, configure PDF Architect to disable script execution in XLS files (check application settings).
3. User Awareness: Train users not to open XLS files from untrusted sources.
4. Application Control: Use AppLocker or Windows Defender Application Control to block untrusted scripts.
5. Network Segmentation: Limit outbound connections from workstations to reduce C2 risk.
6. Alternative Software: Consider using alternative PDF tools that do not process XLS files with macros.

Valters IT
DevSecOps & Cyber Threat Intelligence
This report is provided for educational and defensive purposes only.