CVE-2025-61799

Executive Summary

CVE-2025-61799 is a high-severity out-of-bounds read vulnerability affecting Dassault Systèmes Dimension versions 4.1.4 and earlier. The flaw resides in the parsing of crafted files, where the software reads past the end of an allocated memory structure. This can lead to arbitrary code execution in the context of the current user. Exploitation requires user interaction, specifically opening a malicious file. The vulnerability has a CVSS score of 7.8, indicating a significant risk. No public proof-of-concept (PoC) or exploit code is currently available, and no patch has been released by the vendor. The EPSS score is 0.0%, suggesting low exploitation activity in the wild at this time.

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 (AV): Local (L) – The attacker must have local access to the system.
• Attack Complexity (AC): Low (L) – No special conditions are required for exploitation.
• Privileges Required (PR): None (N) – No privileges are needed to trigger the vulnerability.
• User Interaction (UI): Required (R) – The victim must open a malicious file.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality (C): High (H) – Full data disclosure is possible.
• Integrity (I): High (H) – Full data modification is possible.
• Availability (A): High (H) – Full system availability impact is possible.

Threat Level: High. The vulnerability allows for arbitrary code execution with user interaction. The lack of a patch increases the risk for organizations using affected versions.

Deep Dive & Mechanics

The vulnerability is an out-of-bounds read (CWE-125) in the file parsing logic of Dassault Systèmes Dimension. When the software processes a specially crafted file, it reads data from a memory buffer beyond its allocated boundary. This can lead to the disclosure of sensitive memory contents or, more critically, be leveraged for code execution if the attacker can control the data read.

Technical Details:

• Root Cause: Improper validation of file structure or size during parsing, leading to an off-by-one or similar error.
• Exploitation Mechanism: An attacker crafts a malicious file (e.g., a .dwg or proprietary format) that triggers the out-of-bounds read. By carefully controlling the data read, the attacker can overwrite critical memory structures (e.g., function pointers) to redirect execution flow.
• Impact: Successful exploitation allows the attacker to execute arbitrary code with the privileges of the user opening the file. This could lead to full system compromise, data theft, or installation of malware.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability type, the fix would involve adding bounds checking before memory read operations.

Vulnerable Code (Conceptual):

void parse_file(char *buffer, size_t size) {
    // No bounds check
    int value = *(int *)(buffer + offset);
    // Process value...
}

Patched Code (Conceptual):

void parse_file(char *buffer, size_t size) {
    if (offset + sizeof(int) > size) {
        // Handle error
        return;
    }
    int value = *(int *)(buffer + offset);
    // Process value...
}

Exploitation & Lab Setup

Red Team

Objective: Achieve code execution on a target system running Dimension 4.1.4.

Prerequisites:

• A copy of Dimension 4.1.4 (or earlier) installed on a test VM.
• A debugger (e.g., x64dbg, WinDbg) to analyze memory.
• A fuzzer (e.g., AFL, Boofuzz) to generate crash-inducing inputs.

Steps:

1. Setup: Install Dimension 4.1.4 on a Windows VM.
2. Fuzzing: Use a file fuzzer to generate malformed files targeting the parsing routine. Monitor for crashes.
3. Crash Analysis: Attach a debugger to the Dimension process and open a crashing file. Identify the exact instruction and memory address causing the out-of-bounds read.
4. Exploit Development: Craft a file that triggers the vulnerability and overwrites a critical pointer (e.g., a function pointer in the stack or heap). Use ROP chains or shellcode to execute arbitrary code.
5. Delivery: Send the malicious file to the victim via email, download link, or USB drive.

Example Exploit Snippet (Conceptual):

# Craft a malicious file to trigger out-of-bounds read
import struct

def create_malicious_file():
    # Header
    header = b'\x00' * 0x100
    # Trigger offset
    payload = struct.pack('<I', 0x41424344)  # Controlled data
    # Padding to reach vulnerable function pointer
    payload += b'\x90' * 0x100
    # Overwrite return address
    payload += struct.pack('<Q', 0x7ffa12345678)  # Address of shellcode
    with open('malicious.dim', 'wb') as f:
        f.write(header + payload)

create_malicious_file()

Blue Team

Objective: Detect and prevent exploitation of CVE-2025-61799.

Detection:

• Monitor for unusual file open operations by Dimension.exe.
• Use endpoint detection and response (EDR) to alert on memory access violations.
• Deploy file integrity monitoring (FIM) to detect creation of suspicious files.

Prevention:

• Restrict execution of Dimension to least privilege accounts.
• Use application whitelisting to block unknown binaries.
• Enable ASLR and DEP on the system.
• Isolate the application in a sandbox or virtual environment.

Hunting:

• Search for crash dumps or error logs from Dimension.
• Analyze network traffic for exfiltration attempts post-exploitation.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None available publicly, but monitor for files with unusual structures)
• Process Names: Dimension.exe
• Registry Keys: (None specific)
• Network Indicators: (None specific, but monitor for outbound connections from Dimension)
• YARA Rule: (See Detection Engineering)

Detection Engineering

YARA Rule

rule CVE_2025_61799_Dimension_OOB_Read {
    meta:
        description = "Detects files attempting to exploit CVE-2025-61799 in Dassault Systèmes Dimension"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "unknown"
    strings:
        $s1 = "Dimension" ascii wide nocase
        $s2 = { 00 00 00 00 00 00 00 00 } // Placeholder for specific pattern
    condition:
        $s1 and #s2 > 5
}

Sigma Rule

title: CVE-2025-61799 Exploitation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential exploitation of CVE-2025-61799 via abnormal file access
author: Valters IT
date: 2025/04/10
logsource:
    category: file_event
    product: windows
detection:
    selection:
        Image|endswith: '\Dimension.exe'
        TargetFilename|endswith: '.dim'
    condition: selection
falsepositives:
    - Legitimate use of Dimension
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-61799 Potential Exploit"; flow:to_server; content:"|00 00 00 00|"; depth:100; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate: Disconnect affected systems from the network if possible.
2. Restrict: Limit user permissions to prevent opening untrusted files.
3. Monitor: Enable enhanced logging and alerting for Dimension processes.

Long-term Fix:

• Await an official patch from Dassault Systèmes. Apply as soon as available.
• Consider using a file reputation service to block malicious files.
• Implement application control policies to only allow trusted executables.

Workarounds:

• Use a sandbox or virtual machine to open files from untrusted sources.
• Disable file parsing features if not required.

Valters IT Signature This report was generated by Valters IT Cyber Threat Intelligence. For questions, contact threatintel@valtersit.com.