CVE-2025-7314

Executive Summary

CVE-2025-7314 is a critical memory corruption vulnerability in the IrfanView CADImage Plugin when parsing specially crafted DWG files. The flaw stems from improper validation of user-supplied data, leading to a memory corruption condition that can be leveraged for remote code execution (RCE) in the context of the current process. User interaction is required—the victim must open a malicious DWG file or visit a malicious page that triggers the plugin. With a CVSS score of 7.8, this vulnerability poses a significant risk to systems using IrfanView with the CADImage Plugin, especially in environments where untrusted DWG files are processed. No public exploit or patch is currently available, but the technical details from ZDI (ZDI-CAN-26400) indicate a high likelihood of weaponization.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It affects a Windows-based desktop application plugin (IrfanView CADImage Plugin). No supply chain package security implications exist.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Local (AV:L) – Requires user to open a malicious file.
• Attack Complexity (AC): Low (AC:L) – No special conditions needed.
• Privileges Required (PR): None (PR:N) – No authentication needed.
• User Interaction (UI): Required (UI:R) – Victim must open the file.
• Scope (S): Unchanged (S:U) – Vulnerability affects only the vulnerable component.
• Confidentiality (C): High (C:H) – Full data access possible.
• Integrity (I): High (I:H) – Arbitrary code execution.
• Availability (A): High (A:H) – Potential denial of service or system compromise.

Threat Level: High. The vulnerability is exploitable with low complexity and user interaction, and it can lead to full system compromise in the context of the current user.

Deep Dive & Mechanics

The vulnerability exists in the CADImage Plugin’s handling of DWG file format. DWG files contain binary data structures that define 2D and 3D geometry. The plugin fails to validate the length or boundaries of data read from the file, leading to a buffer overflow or other memory corruption when processing malformed records.

Root Cause: Lack of proper bounds checking on user-supplied data during DWG parsing. An attacker can craft a DWG file with oversized or malformed fields (e.g., entity data, layer names, or block definitions) that cause the plugin to write beyond allocated memory buffers.

Attack Vector: The attacker delivers the malicious DWG file via email, download, or web page. When the victim opens the file with IrfanView (or the plugin is invoked via browser), the parsing routine triggers the memory corruption, allowing the attacker to overwrite critical data structures (e.g., function pointers, return addresses) and redirect execution to shellcode.

Impact: Successful exploitation yields arbitrary code execution with the privileges of the current user. This can lead to data theft, installation of malware, or lateral movement within a network.

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical fix would involve adding input validation and bounds checking. Below is a simplified example of the vulnerable code pattern and a patched version.

Vulnerable Code (C-like pseudocode):

void parse_dwg_record(char *buffer, int size) {
    char name[256];
    int name_len = *(int*)buffer;  // Read length from file
    memcpy(name, buffer + 4, name_len);  // No bounds check
    // Process name...
}

Patched Code:

void parse_dwg_record(char *buffer, int size) {
    char name[256];
    int name_len = *(int*)buffer;
    if (name_len < 0 || name_len > sizeof(name) - 1) {
        // Handle error
        return;
    }
    memcpy(name, buffer + 4, name_len);
    name[name_len] = '\0';
    // Process name...
}

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Windows 10/11 VM with IrfanView 4.67 (or latest) and CADImage Plugin installed.
• Python 3.x for crafting malicious DWG files.
• Debugger (x64dbg) for analysis.

Exploitation Steps:

1. Craft Malicious DWG: Use a fuzzer or manual binary editing to create a DWG file with an oversized field (e.g., a layer name of 1000 bytes).
2. Trigger Vulnerability: Open the file in IrfanView. The plugin will parse the DWG and trigger a buffer overflow.
3. Control Execution: Overwrite a return address or SEH handler with a pointer to shellcode (e.g., a message box or reverse shell).
4. Deliver Payload: Embed shellcode in the DWG file (e.g., in a comment field) and redirect execution to it.

Example Python script to generate a malformed DWG:

import struct

def create_malicious_dwg(filename):
    # Minimal DWG header (simplified)
    header = b'\x41\x43\x31\x30'  # Magic bytes
    # Craft oversized record
    payload = b'A' * 1000  # Overflow data
    # Combine
    with open(filename, 'wb') as f:
        f.write(header + payload)

create_malicious_dwg('exploit.dwg')

Note: This is a conceptual example. Actual exploitation requires precise knowledge of memory layout and offsets.

Blue Team (Defensive)

Detection:

• Monitor for IrfanView crashes (Event ID 1000, Application Error).
• Use process monitoring to detect abnormal memory access patterns.
• Deploy YARA rules to scan for malformed DWG files.

Prevention:

• Disable the CADImage Plugin if not needed.
• Use application whitelisting to prevent IrfanView from executing untrusted files.
• Implement file reputation services to block suspicious DWG files.

Hunting:

• Search for DWG files with unusually large fields (e.g., layer names > 255 bytes).
• Analyze crash dumps for signs of exploitation (e.g., shellcode in memory).

Indicators of Compromise (IOCs)

• File Hashes: (Example – replace with actual if available)
  • malicious.dwg – SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network: Outbound connections from IrfanView process (e.g., to attacker C2).
• Process: i_view32.exe or i_view64.exe crashing with exception code 0xc0000005 (access violation).
• Registry: Unusual modifications to IrfanView plugin settings.
• Memory: Presence of shellcode patterns (e.g., \x90\x90\x90\x90 NOP sleds) in process memory.

Detection Engineering

YARA Rule

rule CVE_2025_7314_DWG_Malicious {
    meta:
        description = "Detects malformed DWG files exploiting CVE-2025-7314"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-7314"
    strings:
        $dwg_magic = { 41 43 31 30 }  // AC10
        $overflow = /[A-Za-z0-9]{500,}/  // Large field
    condition:
        $dwg_magic at 0 and #overflow > 0
}

Sigma Rule

title: IrfanView CADImage Plugin Crash
id: 7b8f9a1c-3d4e-5f6a-7b8c-9d0e1f2a3b4c
status: experimental
description: Detects IrfanView crashes potentially caused by CVE-2025-7314 exploitation
author: Valters IT
logsource:
    product: windows
    service: application
detection:
    selection:
        EventID: 1000
        Application: 'i_view*.exe'
        ExceptionCode: '0xc0000005'
    condition: selection
falsepositives:
    - Legitimate crashes due to corrupted files
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-7314 IrfanView DWG Exploit Outbound"; flow:to_server; content:"|41 43 31 30|"; depth:4; content:"|90 90 90 90|"; distance:0; within:100; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the CADImage Plugin: Remove or rename the plugin DLL (e.g., CADImage.dll) in the IrfanView plugins folder.
2. User Awareness: Train users not to open DWG files from untrusted sources.
3. File Filtering: Block DWG files at email gateways and web proxies.

Long-Term Fix:

• Monitor vendor for an official patch. If none is released, consider replacing IrfanView with an alternative image viewer that supports DWG files securely.
• Implement application sandboxing (e.g., Windows Defender Application Guard) to isolate IrfanView.

Workaround:

• Use a dedicated DWG viewer (e.g., Autodesk DWG TrueView) instead of IrfanView for CAD files.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert