CVE-2025-2024

Executive Summary

CVE-2025-2024 is a critical uninitialized variable vulnerability in Trimble SketchUp, a widely used 3D modeling application. The flaw resides in the parsing of SKP files, where memory is accessed before proper initialization. This allows a remote attacker to execute arbitrary code in the context of the current process by tricking a user into opening a malicious SKP file or visiting a crafted web page. With a CVSS score of 7.8, the vulnerability requires user interaction but poses a severe risk to confidentiality, integrity, and availability. No public proof-of-concept (PoC) or patch is currently available, making this a high-priority zero-day for defenders.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a standalone desktop application (Trimble SketchUp) and its SKP file format. Organizations using SketchUp in their design or engineering workflows should treat this as a critical supply chain risk, as malicious SKP files could be delivered via email, downloads, or shared project files.

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
• Threat Level: Critical (zero-day, unpatched, remote code execution)

Deep Dive & Mechanics

The vulnerability is a classic uninitialized memory access (CWE-457) in Trimble SketchUp's SKP file parser. When parsing a specially crafted SKP file, the parser fails to initialize a memory buffer before reading data into it. This means the buffer contains residual data from previous allocations (heap memory). An attacker can control the structure of the SKP file to influence what data is read into this uninitialized buffer, potentially leading to:

1. Information Disclosure: The uninitialized memory may leak sensitive data from the process heap.
2. Code Execution: By carefully crafting the SKP file, the attacker can overwrite function pointers or other critical data structures in the uninitialized region, redirecting execution flow to attacker-controlled shellcode.

The vulnerability was reported via the ZDI program (ZDI-CAN-25210) and affects all versions of Trimble SketchUp prior to any patch. The exact vulnerable version range is unknown, but the flaw exists in the core SKP parsing engine.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, the vulnerable code pattern is typical:

Vulnerable (pseudo-code):

void parse_skp_data(FILE *file) {
    char buffer[256];
    // buffer is NOT initialized
    read(file, buffer, sizeof(buffer)); // reads into uninitialized memory
    // process buffer...
}

Patched (expected fix):

void parse_skp_data(FILE *file) {
    char buffer[256] = {0}; // initialize to zero
    read(file, buffer, sizeof(buffer));
    // process buffer...
}

The fix would involve zero-initializing all memory buffers before use, or using safer parsing functions that handle initialization automatically.

Exploitation & Lab Setup

Red Team (Exploitation)

No public exploit code is available. However, a theoretical exploitation approach would involve:

1. Crafting a Malicious SKP File: Use a hex editor or custom script to modify a legitimate SKP file, inserting a payload that triggers the uninitialized memory vulnerability.
2. Delivering the File: Send the file via email, upload to a shared drive, or host on a malicious website.
3. Triggering the Vulnerability: The victim opens the SKP file in Trimble SketchUp. The parser reads the uninitialized buffer, and the attacker-controlled data overwrites a critical pointer.
4. Code Execution: The overwritten pointer redirects execution to shellcode embedded in the SKP file, granting the attacker code execution in the user's context.

Lab Setup:

• Victim: Windows 10/11 with Trimble SketchUp (any unpatched version).
• Attacker: Kali Linux with Metasploit or custom Python script to generate malicious SKP.
• Tools: msfvenom for shellcode, python with struct module for file crafting.

Example (conceptual):

# This is a conceptual example; no working exploit exists.
import struct

def craft_malicious_skp():
    # Placeholder for SKP file structure
    payload = b"A" * 256  # trigger uninitialized buffer
    # Overwrite return address with shellcode address
    payload += struct.pack("<I", 0x41414141)  # placeholder
    with open("malicious.skp", "wb") as f:
        f.write(payload)

craft_malicious_skp()

Blue Team (Defense)

• User Awareness: Train users not to open SKP files from untrusted sources.
• File Scanning: Use endpoint detection and response (EDR) tools to scan SKP files for anomalies.
• Application Sandboxing: Run SketchUp in a sandboxed environment to limit the impact of exploitation.
• Network Segmentation: Restrict access to shared drives where SKP files are stored.
• Monitoring: Monitor for unusual child processes spawned by SketchUp (e.g., cmd.exe, powershell.exe).

Indicators of Compromise (IOCs)

• File Hashes (SHA256): No known malicious samples yet.
• Network Indicators: Outbound connections from SketchUp process to unknown IPs (potential C2).
• Process Anomalies: sketchup.exe spawning cmd.exe, powershell.exe, or rundll32.exe.
• Registry Changes: Unusual registry modifications under HKCU\Software\Trimble\SketchUp.
• File System: Creation of .dll or .exe files in the SketchUp installation directory.

Detection Engineering

YARA Rule

rule CVE_2025_2024_SKP_Uninitialized {
    meta:
        description = "Detects malicious SKP files exploiting CVE-2025-2024"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-2024"
    strings:
        $skp_header = { 00 00 00 00 53 4B 50 } // SKP magic bytes (example)
        $suspicious_pattern = { 41 41 41 41 41 41 41 41 } // long A's
    condition:
        $skp_header at 0 and #suspicious_pattern > 10
}

Sigma Rule

title: CVE-2025-2024 - Trimble SketchUp Uninitialized Variable RCE
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects exploitation attempts of CVE-2025-2024 via process anomalies
author: Valters IT
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\sketchup.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\rundll32.exe'
    condition: selection
falsepositives:
    - Legitimate use of command line tools by SketchUp (rare)
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"CVE-2025-2024 - Potential SKP file download from malicious site"; flow:to_server,established; content:"|53 4B 50|"; distance:0; within:3; fileext:"skp"; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Discontinue use of Trimble SketchUp until a patch is available. Use alternative 3D modeling software.
• Workaround: If SketchUp is essential, run it in a sandboxed environment (e.g., Windows Sandbox, Firejail) with restricted network access.
• User Training: Educate users to never open SKP files from untrusted sources.
• File Blocking: Block SKP file attachments at the email gateway and web proxy.
• Monitoring: Deploy the provided YARA, Sigma, and Suricata rules to detect exploitation attempts.
• Vendor Contact: Monitor Trimble's security advisories for patch releases.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert