CVE-2025-1045

Executive Summary

CVE-2025-1045 is a critical heap-based buffer overflow vulnerability in Luxion KeyShot Viewer, specifically during the parsing of KSP files. The flaw allows remote attackers to execute arbitrary code in the context of the current process, requiring user interaction (e.g., opening a malicious KSP file or visiting a malicious page). With a CVSS score of 7.8, this vulnerability poses a significant risk to users of KeyShot Viewer, especially in environments where untrusted KSP files are processed. No public exploit or patch is currently available, but the vulnerability is actively tracked by ZDI (ZDI-CAN-24586).

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It affects a standalone desktop application (Luxion KeyShot Viewer) and does not involve package manager dependencies.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector: Local (requires user to open a malicious file)
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: High. Exploitation could lead to full compromise of the affected system, including data theft, malware installation, or lateral movement.

Deep Dive & Mechanics

The vulnerability resides in the KSP file parser of Luxion KeyShot Viewer. KSP files are proprietary scene/project files used by KeyShot for 3D rendering. The parser fails to validate the length of user-supplied data before copying it to a heap-based buffer, leading to a classic heap overflow.

Technical Details:

• Root Cause: Lack of bounds checking on a user-controlled length field in the KSP file format.
• Trigger: A specially crafted KSP file containing an oversized data chunk.
• Impact: Overwriting adjacent heap memory, which can be leveraged to hijack execution flow and achieve arbitrary code execution.
• Exploitation Prerequisites: The target must open the malicious KSP file using KeyShot Viewer. No additional privileges are required.

Attack Scenario:

1. Attacker crafts a malicious KSP file with a heap overflow payload.
2. Attacker distributes the file via email, social engineering, or malicious websites.
3. Victim opens the file in KeyShot Viewer, triggering the overflow.
4. Attacker gains code execution in the context of the KeyShot Viewer process.

Vulnerable vs. Patched Code

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

// Vulnerable pseudo-code
void parse_ksp_data(char *input, size_t input_len) {
    char *buffer = malloc(256);
    memcpy(buffer, input, input_len); // No length check
}

A patched version would include proper bounds checking:

// Patched pseudo-code
void parse_ksp_data(char *input, size_t input_len) {
    char *buffer = malloc(256);
    if (input_len > 256) {
        // Handle error or truncate
        return;
    }
    memcpy(buffer, input, input_len);
}

Exploitation & Lab Setup

Red Team (Exploitation)

No public exploit code is available. However, a hypothetical exploit would involve:

1. Crafting a Malicious KSP File: Use a hex editor or custom script to modify a legitimate KSP file, inserting a large data chunk that overflows the heap buffer.
2. Heap Spraying: Prepare the heap with controlled data to ensure the overflow overwrites a critical function pointer or return address.
3. Payload Delivery: Embed shellcode or ROP chain in the overflow data.
4. Trigger: Open the file in KeyShot Viewer.

Example (Conceptual):

# Hypothetical exploit script (not functional)
import struct

def craft_ksp_overflow():
    payload = b"A" * 256  # Fill buffer
    payload += struct.pack("<I", 0xdeadbeef)  # Overwrite heap metadata
    payload += b"\x90" * 100  # NOP sled
    payload += shellcode  # Arbitrary code
    # Write to KSP file
    with open("malicious.ksp", "wb") as f:
        f.write(payload)

Blue Team (Defense)

• User Awareness: Train users to avoid opening KSP files from untrusted sources.
• Application Sandboxing: Run KeyShot Viewer in a sandboxed environment (e.g., Windows Sandbox, Firejail).
• File Scanning: Use endpoint security solutions to scan KSP files for anomalous structures.
• Behavioral Monitoring: Monitor KeyShot Viewer for abnormal memory access patterns or crashes.

Indicators of Compromise (IOCs)

• File Hashes (Example):
  • malicious.ksp SHA256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Indicators: None specific (exploitation is local).
• Process Anomalies:
  • KeyShot Viewer process (ksviewer.exe) crashing repeatedly.
  • Unusual child processes spawned by KeyShot Viewer.
• Registry/File System:
  • Unexpected files written to %TEMP% or %APPDATA% by KeyShot Viewer.

Detection Engineering

YARA Rule

rule CVE_2025_1045_KeyShot_HeapOverflow {
    meta:
        description = "Detects malicious KSP files exploiting CVE-2025-1045"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-1045"
    strings:
        $ksp_magic = { 4B 53 50 46 } // "KSPF" magic bytes
        $overflow_pattern = { 41 41 41 41 41 41 41 41 } // Large block of 'A's
    condition:
        $ksp_magic at 0 and #overflow_pattern > 10
}

Sigma Rule

title: CVE-2025-1045 KeyShot Viewer Heap Overflow
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects KeyShot Viewer crashes or abnormal memory access indicative of CVE-2025-1045 exploitation
author: Valters IT
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\ksviewer.exe'
        CommandLine|contains: '.ksp'
    condition: selection
falsepositives:
    - Legitimate large KSP files
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-1045 KeyShot Viewer KSP File Download"; flow:to_client,established; file.name:/.*\.ksp/i; file.size:>1000000; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate Actions:
  • Disable or restrict the use of KeyShot Viewer until a patch is available.
  • Implement application whitelisting to prevent execution of untrusted KSP files.
• Long-term Fix:
  • Monitor Luxion’s official channels for a security update.
  • Apply vendor patch as soon as it is released.
• Compensating Controls:
  • Use endpoint detection and response (EDR) tools to monitor for heap overflow behavior.
  • Enable Windows Defender Exploit Guard (Heap Spray protection).

Valters IT