CVE-2018-25227

Executive Summary

CVE-2018-25227 is a denial of service (DoS) vulnerability in Valentina Studio version 9.0.4. The flaw allows a local attacker to crash the application by supplying an excessively long string (256 bytes) in the Host field during server connection attempts. This is a classic buffer overflow or input validation issue (CWE-20) that can be triggered by pasting a crafted buffer into the Host parameter. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), but based on the description, it is a local DoS with low complexity and no privileges required, though user interaction is needed. No patch is currently available, and no public exploit code or Nuclei template exists. The EPSS score is 0.0%, indicating very low exploitation activity in the wild.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a standalone desktop application (Valentina Studio) and does not involve supply chain dependencies.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
• Base Score: 5.5 (Medium)
• Attack Vector: Local (AV:L) – The attacker must have local access to the system.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: Required (UI:R) – The victim must paste the malicious string.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: None (C:N)
• Integrity Impact: None (I:N)
• Availability Impact: High (A:H) – Application crash leads to denial of service.

Threat Level: Medium. The vulnerability requires local access and user interaction, limiting its impact. However, it can be used to disrupt operations in shared environments.

Deep Dive & Mechanics

The vulnerability resides in the Host field of Valentina Studio's server connection dialog. When a user attempts to connect to a database server, the application parses the Host parameter. If the input exceeds 256 bytes (specifically a buffer of repeated characters), the application fails to properly validate the length, leading to a buffer overflow or memory corruption that crashes the process.

Root Cause: Improper input validation (CWE-20) – the application does not enforce a maximum length on the Host field before processing it.

Attack Vector: Local attacker crafts a string of 256 repeated characters (e.g., "A"*256) and convinces a victim to paste it into the Host field and attempt a connection. The crash occurs immediately upon connection attempt.

Impact: Denial of service – the application becomes unresponsive and must be restarted. No data is compromised, but productivity is affected.

Vulnerable vs. Patched Code

Vulnerable Code (Valentina Studio 9.0.4):

// Pseudocode for vulnerable Host field handling
void connectToServer(char *host) {
    char buffer[256];
    strcpy(buffer, host); // No bounds checking
    // ... connection logic
}

Patched Code (Hypothetical):

void connectToServer(char *host) {
    char buffer[256];
    if (strlen(host) >= 256) {
        // Reject input
        return;
    }
    strcpy(buffer, host);
    // ... connection logic
}

Note: No official patch is available. The above is a recommended fix.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Valentina Studio 9.0.4 installed on a Windows/macOS/Linux system.
• Local access to the machine (physical or remote desktop).

Steps:

1. Generate the malicious payload:

   # payload.py
   payload = "A" * 256
   print(payload)
   

2. Copy the output (256 'A's).
3. Open Valentina Studio and navigate to the server connection dialog.
4. Paste the payload into the Host field.
5. Click "Connect" or equivalent button.
6. The application will crash immediately.

Expected Outcome: Valentina Studio terminates with an error or becomes unresponsive.

Blue Team (Detection & Prevention)

Detection:

• Monitor for unusual input lengths in Valentina Studio logs (if available).
• Use process monitoring to detect crashes (e.g., Event ID 1000 on Windows).
• Deploy application whitelisting to block untrusted input.

Prevention:

• Apply input validation at the application level (if source code is available).
• Use a proxy or input sanitizer for database connections.
• Educate users not to paste unknown strings into connection fields.

Indicators of Compromise (IOCs)

• File/Process: Valentina Studio process crash (e.g., valentina-studio.exe terminates unexpectedly).
• Log Entry: Application error logs showing buffer overflow or access violation.
• Network: No network IOCs – the attack is local.
• Payload: String of 256 repeated characters (e.g., "AAAA...A" of length 256).

Detection Engineering

YARA Rule

rule CVE_2018_25227_Valentina_Studio_DoS {
    meta:
        description = "Detects payload for CVE-2018-25227 in Valentina Studio"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2018-25227"
    strings:
        $payload = /[A-Za-z0-9]{256}/ // Matches any 256-character string
    condition:
        $payload
}

Sigma Rule

title: Valentina Studio DoS via Long Host Field
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to exploit CVE-2018-25227 by supplying a 256-byte string in the Host field.
author: Valters IT
date: 2025/04/10
logsource:
    product: windows
    service: application
detection:
    selection:
        EventID: 1000
        Application: "valentina-studio.exe"
        ExceptionCode: "0xc0000005" // Access violation
    condition: selection
falsepositives:
    - Legitimate long hostnames (unlikely)
level: medium

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2018-25227 Valentina Studio DoS Attempt"; content:"|41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41|"; depth:256; sid:1000001; rev:1;)

Note: This rule detects the payload (256 'A's) in network traffic, though the attack is local. Adjust for local detection if needed.

Remediation & Mitigation

Immediate Actions:

1. Upgrade: Check for updates from Valentina (valentina-db.com). If no patch exists, consider using an alternative database management tool.
2. Input Validation: If you have access to the source code, implement length checks on the Host field (max 255 characters).
3. User Training: Educate users not to paste unknown strings into connection fields.

Long-Term Mitigation:

• Application Hardening: Use memory-safe languages or add bounds checking.
• Monitoring: Deploy endpoint detection and response (EDR) to monitor for application crashes.
• Virtualization: Run Valentina Studio in a sandboxed environment to limit impact.

Workaround: None available. The only mitigation is to avoid using the vulnerable version or restrict local access.

Valters IT

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