attack-surface.md

Attack Surface Analysis for monicahq/monica

Attack Surface: Stored Cross-Site Scripting (XSS) via Contact Fields

• Description: Malicious JavaScript code is injected into contact fields (name, address, custom fields, etc.) and stored in the database. When other users view the affected contact, the script executes in their browser.
• Monica Contribution: Monica's core functionality of storing and displaying contact information, including user-defined custom fields, relies on user input that might not be properly sanitized before being stored and rendered. This is a direct feature of Monica and its data handling.
• Example: An attacker injects <script>alert('XSS Vulnerability!')</script> into the "Notes" field of a contact. When a user views this contact, the alert box pops up, demonstrating script execution. In a real attack, this could be used to steal session cookies, redirect users to malicious sites, or deface the application.
• Impact: Account compromise, data theft, defacement of the application, phishing attacks targeting users of the CRM.
• Risk Severity: High
• Mitigation Strategies:
  • Developer: Implement robust input validation and output encoding for all contact fields. Use context-aware output encoding (e.g., HTML entity encoding for HTML context, JavaScript escaping for JavaScript context) when displaying contact data. Utilize a Content Security Policy (CSP) to further restrict the execution of inline scripts and control resource loading. Regularly audit code for XSS vulnerabilities.

Attack Surface: Stored Cross-Site Scripting (XSS) via Notes and Activities

• Description: Similar to contact fields, malicious JavaScript is injected into notes or activity descriptions and stored. This script executes when other users view these notes or activities.
• Monica Contribution: The note-taking and activity logging features in Monica allow free-form text input, which, if not properly sanitized, can be exploited for stored XSS. This is a core feature of Monica for user interaction and data recording.
• Example: An attacker adds a note with Markdown containing an image tag with an onerror attribute: ![alt text](invalid-url "title" onerror="alert('XSS via Markdown!')"). If the Markdown parser or rendering process within Monica is vulnerable, this could trigger JavaScript execution.
• Impact: Account compromise, data theft, defacement, phishing attacks.
• Risk Severity: High
• Mitigation Strategies:
  • Developer: Implement robust input validation and output encoding for notes and activity descriptions. Carefully configure and secure the Markdown parser (if used within Monica). Consider using a sanitizing Markdown parser that removes potentially dangerous HTML tags and attributes. Implement CSP. Regularly audit code for XSS vulnerabilities in note and activity handling.

Attack Surface: Unrestricted File Upload leading to Remote Code Execution

• Description: Lack of proper file type validation and upload restrictions allows attackers to upload malicious executable files (e.g., PHP scripts) through avatar upload functionality. If the web server is misconfigured to execute these files, this vulnerability in Monica's file handling can lead to remote code execution on the server.
• Monica Contribution: Monica's avatar upload feature, a direct component of the application, if not secured within Monica's code, provides a potential entry point for file upload attacks. The vulnerability lies in how Monica handles and processes file uploads.
• Example: An attacker uploads a PHP file named evil.php containing backdoor code as their avatar using Monica's upload form. If the web server executes PHP files in the upload directory (due to misconfiguration and Monica's upload handling not preventing this), accessing https://monica.example.com/uploads/avatars/evil.php could execute the attacker's code on the server.
• Impact: Full server compromise, data breach, denial of service, malware distribution.
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer: Implement strict file type validation on the server-side within Monica's upload handling logic, allowing only safe image file types (e.g., PNG, JPG, GIF). Do not rely on client-side validation. Store uploaded files outside the webroot if possible. If files must be within the webroot, ensure Monica's code and server configuration work together to prevent execution of scripts in the upload directory (e.g., using .htaccess or web server configuration directives enforced by Monica's setup). Implement file size limits within Monica's upload processing. Use vulnerability scanning tools to check Monica's code for file upload vulnerabilities.

Attack Surface: Insecure API Authentication/Authorization (if API is enabled/exposed)

• Description: Weak or flawed authentication and authorization mechanisms in Monica's API (if exposed) allow unauthorized access to API endpoints, potentially leading to data breaches or unauthorized actions. The vulnerability resides in Monica's API implementation.
• Monica Contribution: If Monica exposes an API for integrations or mobile apps (as part of its features or extensions), vulnerabilities in its API security implementation are a direct contribution to the attack surface. This is about how Monica's API is designed and secured.
• Example: An API endpoint within Monica to retrieve contact details is protected only by a weak, easily guessable API key hardcoded in Monica's client-side code. An attacker extracts the API key and uses it to access sensitive contact information without proper authorization. Or, an API endpoint in Monica uses predictable IDs without proper authorization checks, allowing an attacker to access data belonging to other users (IDOR - Insecure Direct Object Reference) through Monica's API.
• Impact: Data breach, unauthorized data modification, account takeover, denial of service.
• Risk Severity: High to Critical (depending on the sensitivity of data exposed via API and the extent of API functionality)
• Mitigation Strategies:
  • Developer: Implement strong API authentication mechanisms within Monica's API code (e.g., OAuth 2.0, JWT). Use strong, randomly generated API keys and rotate them regularly. Implement robust authorization checks within Monica's API logic to ensure users can only access data they are permitted to access (least privilege principle). Enforce rate limiting on API endpoints within Monica's API layer to prevent abuse and DoS attacks. Regularly audit Monica's API security code.

Attack Surface: Vulnerable Third-Party Dependencies

• Description: Monica relies on third-party PHP and JavaScript libraries. Known vulnerabilities in these dependencies, when present in the versions used by Monica, can be exploited to compromise the application. The risk is directly tied to Monica's choice and management of dependencies.
• Monica Contribution: Monica's dependency on external libraries means it inherits the security risks associated with those libraries. Outdated or vulnerable dependencies used by Monica directly increase Monica's attack surface. The responsibility to manage and update these dependencies falls on the Monica development and maintenance process.
• Example: Monica uses an outdated version of a JavaScript library with a known XSS vulnerability. An attacker exploits this vulnerability by crafting a specific request that targets the vulnerable code within Monica's application that utilizes this library, leading to XSS.
• Impact: Varies depending on the vulnerability, but can range from XSS and data breaches to remote code execution, all impacting the Monica application and its data.
• Risk Severity: Medium to Critical (depending on the severity of the dependency vulnerability - High/Critical vulnerabilities in dependencies are the focus here). For this refined list, we will consider this as High to Critical if the potential impact of a dependency vulnerability is high or critical on Monica.
• Mitigation Strategies:
  • Developer: Regularly update all third-party dependencies (PHP libraries, JavaScript libraries, etc.) used by Monica to the latest versions. Use dependency scanning tools (e.g., Composer audit, npm audit, Snyk) to identify and remediate known vulnerabilities in dependencies within Monica's project. Implement a process for monitoring and patching dependency vulnerabilities as part of Monica's development and maintenance.