CVE-2025-9031

Executive Summary

CVE-2025-9031 is an Observable Timing Discrepancy vulnerability (CWE-208) affecting DivvyDrive Web versions 4.8.2.2 through 4.8.2.14. This vulnerability allows an unauthenticated attacker to perform cross-domain search timing attacks, potentially leaking sensitive information through response time differences. The vulnerability has a CVSS score of 4.3 (Medium) and currently has no known public exploit code or active exploitation in the wild (EPSS 0.0%). The vendor, DivvyDrive Information Technologies Inc., has released a patched version (4.8.2.15) to address this issue.

Supply Chain & Package Security

This vulnerability is not related to any open-source package manager (NPM, PyPI, Go, Ruby). It affects a proprietary web application, DivvyDrive Web. Organizations using DivvyDrive Web should verify their version and apply the vendor-supplied patch immediately.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: Low (C:L)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

Threat Level: Medium. The vulnerability allows information disclosure through timing side-channels but does not enable direct data manipulation or denial of service.

Deep Dive & Mechanics

The vulnerability resides in the cross-domain search functionality of DivvyDrive Web. When processing search requests from different origins, the application exhibits observable timing discrepancies based on the existence or non-existence of certain data. An attacker can exploit this by:

1. Sending crafted search requests from a malicious website (cross-domain) to the DivvyDrive Web application.
2. Measuring the response time for each request.
3. Correlating timing differences to infer the presence or absence of specific records, user accounts, or other sensitive information.

The root cause is the lack of constant-time comparison or response masking in the search logic. The application likely performs different code paths or database queries depending on whether a match is found, leading to measurable time differences.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Vulnerable: Timing depends on search result
function search(query) {
    let result = database.find(query);
    if (result) {
        // Process found result (takes longer)
        return formatResult(result);
    } else {
        // Return empty quickly
        return "No results";
    }
}

Patched Code (Conceptual):

// Patched: Constant-time response
function search(query) {
    let result = database.find(query);
    let response = "No results";
    if (result) {
        response = formatResult(result);
    }
    // Artificial delay to normalize timing
    sleep(50); // Fixed delay
    return response;
}

The patch introduces a fixed artificial delay to mask timing differences, ensuring that responses for found and not-found queries take approximately the same amount of time.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable DivvyDrive Web instance (version 4.8.2.2 to 4.8.2.14) in a controlled environment.
2. Use a tool like Burp Suite or a custom Python script to send cross-origin requests.
3. Measure response times using precise timing (e.g., time.time() in Python).

Exploitation Steps:

1. Identify the search endpoint (e.g., /api/search).
2. Send a series of search queries with known and unknown values.
3. Record response times for each query.
4. Analyze timing differences to infer sensitive data (e.g., valid usernames, file existence).

Example Python Script:

import requests
import time

target = "http://vulnerable-divvydrive.com/api/search"
queries = ["admin", "test", "nonexistent_user_12345"]

for q in queries:
    start = time.time()
    r = requests.get(target, params={"q": q})
    elapsed = time.time() - start
    print(f"Query '{q}': {elapsed:.4f}s - Status: {r.status_code}")

Blue Team

Detection Steps:

1. Monitor for unusual cross-origin requests to search endpoints.
2. Look for patterns of repeated search queries with varying parameters.
3. Analyze response time anomalies in web server logs.
4. Implement Web Application Firewall (WAF) rules to block or rate-limit cross-origin search requests.

Hunting Query (Splunk):

index=web_logs source="/var/log/nginx/access.log"
| search uri="/api/search*"
| eval response_time = (response_time_ms / 1000)
| stats avg(response_time) as avg_time, count by src_ip, uri
| where avg_time > 0.5

Indicators of Compromise (IOCs)

• Network IOCs:

  • Unusual cross-origin requests to /api/search or similar endpoints.
  • High volume of search queries from a single IP address.
  • Requests with Origin headers from unexpected domains.

• Host IOCs:

  • Web server logs showing abnormal response time patterns.
  • Increased CPU usage on the web server due to repeated search queries.

• File IOCs:

  • Log entries containing timing-related anomalies (e.g., response times > 1 second for simple queries).

Detection Engineering

YARA Rule

rule CVE_2025_9031_Timing_Discrepancy {
    meta:
        description = "Detects potential timing attack attempts against DivvyDrive Web"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-9031"
    strings:
        $search_endpoint = "/api/search" nocase
        $cross_origin = "Origin:" nocase
        $timing_header = "X-Response-Time:" nocase
    condition:
        $search_endpoint and (#cross_origin > 5) and $timing_header
}

Sigma Rule

title: CVE-2025-9031 - Observable Timing Discrepancy in DivvyDrive Web
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential exploitation attempts of CVE-2025-9031 via cross-domain search timing attacks
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: nginx
detection:
    selection:
        uri: "/api/search*"
        http_method: "GET"
        origin|contains: 
            - "http://"
            - "https://"
    condition: selection
falsepositives:
    - Legitimate cross-origin API calls from trusted domains
level: medium

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-9031 - Potential DivvyDrive Web Timing Attack";
    flow:to_server,established;
    content:"/api/search"; http_uri;
    pcre:"/Origin:\s*https?:\/\//iH";
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Upgrade DivvyDrive Web to version 4.8.2.15 or later.
2. If immediate patching is not possible, implement a Web Application Firewall (WAF) rule to block cross-origin requests to search endpoints.
3. Add artificial delays to search responses to normalize timing.

Long-term Measures:

1. Conduct a security audit of all API endpoints for timing side-channel vulnerabilities.
2. Implement constant-time comparison functions for all sensitive operations.
3. Monitor for unusual cross-origin request patterns.

Workarounds:

• Restrict CORS (Cross-Origin Resource Sharing) policies to only allow trusted domains.
• Rate-limit search requests per IP address.
• Disable cross-domain search functionality if not required.

Valters IT
Securing Digital Frontiers