attack-surface.md

Attack Surface Analysis for seldaek/monolog

Attack Surface: File System Vulnerabilities (via StreamHandler/RotatingFileHandler)

Description: Misconfiguration or vulnerabilities related to file-based log handlers can lead to file system access issues.

Monolog Contribution: Monolog's StreamHandler and RotatingFileHandler write logs to files. Misconfiguration of file paths or permissions in Monolog handler configuration directly creates vulnerabilities.

Example:

• Path Traversal: If the log file path in StreamHandler or RotatingFileHandler configuration is constructed using unsanitized user input (highly discouraged but possible through external configuration injection), an attacker might manipulate input to write logs to arbitrary file paths outside the intended log directory.
• DoS (Disk Exhaustion): Incorrectly configured logging levels or application errors leading to excessive log generation via StreamHandler or RotatingFileHandler, filling up disk space and causing a Denial of Service.
• Information Disclosure (Permissions): Log files created by StreamHandler or RotatingFileHandler are created with overly permissive permissions due to misconfiguration or default system settings, allowing unauthorized users to access sensitive information in logs.

Impact:

• Path Traversal: Arbitrary file write, potentially leading to code execution or configuration modification.
• DoS (Disk Exhaustion): Application downtime, system instability.
• Information Disclosure: Exposure of sensitive data in logs.

Risk Severity: High (Path Traversal can be High, DoS and Information Disclosure Medium, but Path Traversal elevates overall risk to High in this context due to direct Monolog configuration involvement).

Mitigation Strategies:

• Hardcoded or Parameterized File Paths in Monolog Configuration: Avoid constructing log file paths dynamically within Monolog handler configuration. Use hardcoded paths or parameterized configuration that is securely managed and not influenced by user input.
• Principle of Least Privilege (File Permissions): Ensure the user running the application and Monolog has the minimum necessary permissions to write to the log directory. Configure file creation modes in StreamHandler and RotatingFileHandler to set restrictive file permissions.
• Log Rotation and Management: Utilize RotatingFileHandler or external log rotation tools to prevent disk space exhaustion. Configure appropriate rotation policies within Monolog.
• Resource Limits: Implement system-level resource limits (e.g., disk quotas) to mitigate DoS through excessive logging, independent of Monolog configuration.

Attack Surface: Database Vulnerabilities (via Database Handlers)

Description: Using database handlers (e.g., DoctrineDBALHandler, PdoHandler) can introduce database-related vulnerabilities if handler configuration is insecure or if custom handlers are poorly implemented.

Monolog Contribution: Monolog provides handlers to write logs to databases. Insecure configuration of database connection parameters or poorly implemented custom database handlers directly contribute to vulnerabilities.

Example:

• Credential Exposure: Database credentials (username, password) for database handlers are hardcoded in Monolog handler configurations or stored insecurely in configuration files used by Monolog, making them vulnerable to exposure if configuration files are compromised.

Impact:

• Credential Exposure: Unauthorized database access, data breach.

Risk Severity: High

Mitigation Strategies:

• Secure Credential Management for Monolog Handlers: Store database credentials securely using environment variables, configuration management tools, or dedicated secret management systems outside of direct Monolog configuration files. Access these secure credentials within the application and pass them to Monolog handler configuration programmatically. Avoid hardcoding credentials in Monolog configuration files.
• Principle of Least Privilege (Database Access): Configure the database user used by Monolog logging handlers with the minimum necessary permissions (e.g., INSERT only) on the logging table. This is configured outside of Monolog, but is a crucial mitigation for database handler usage.
• Regular Security Audits: Review Monolog configurations and custom database handlers (if any) for potential credential exposure or insecure database interaction patterns.

Attack Surface: Email Vulnerabilities (via Email Handlers)

Description: Using email handlers (e.g., NativeMailerHandler, SwiftMailerHandler) can introduce email-related vulnerabilities through insecure credential management in handler configuration.

Monolog Contribution: Monolog provides handlers to send log messages via email. Insecure storage of SMTP credentials within Monolog handler configuration directly contributes to credential exposure risks.

Example:

• Credential Exposure: SMTP server credentials (username, password) are insecurely stored in Monolog handler configurations, making them vulnerable to exposure if configuration files are compromised.

Impact:

• Credential Exposure: Unauthorized access to email accounts or SMTP servers.

Risk Severity: High

Mitigation Strategies:

• Secure Credential Management for Monolog Email Handlers: Store SMTP credentials securely using environment variables, secret management systems, or secure configuration management outside of direct Monolog configuration files. Access these secure credentials within the application and pass them to Monolog handler configuration programmatically. Avoid hardcoding credentials in Monolog configuration files.
• TLS/SSL for Email: Configure email handlers to use TLS/SSL encryption for email transmission to protect confidentiality. This is a configuration option within Monolog handlers.
• Principle of Least Privilege (Email Accounts): Use dedicated email accounts for logging purposes with limited privileges. This is a broader security practice, but relevant to Monolog email handler usage.

Attack Surface: External Service Vulnerabilities (via External Service Handlers)

Description: Using handlers that send logs to external services (e.g., SlackHandler, TelegramBotHandler, SyslogHandler) can introduce vulnerabilities related to insecure API key/token management in handler configuration.

Monolog Contribution: Monolog provides handlers to integrate with various external services. Insecure storage of API keys or tokens within Monolog handler configuration directly contributes to credential exposure risks.

Example:

• API Key/Token Exposure: API keys or tokens for external services are hardcoded in Monolog handler configurations or stored insecurely, allowing attackers to steal them if configuration files are compromised.

Impact:

• API Key/Token Exposure: Unauthorized access to external services, abuse of services.

Risk Severity: High

Mitigation Strategies:

• Secure Credential Management for Monolog External Service Handlers: Store API keys and tokens securely using environment variables, secret management systems, or secure configuration management outside of direct Monolog configuration files. Access these secure credentials within the application and pass them to Monolog handler configuration programmatically. Avoid hardcoding them in Monolog configuration files.
• Principle of Least Privilege (API Keys): Use API keys with the minimum necessary permissions for logging purposes. This is a broader security practice, but relevant to Monolog external service handler usage.
• TLS/SSL for External Service Communication: Ensure communication with external services is encrypted using TLS/SSL. This is often handled by the underlying libraries used by Monolog handlers, but should be verified.
• Regular Security Audits: Review Monolog configurations and integrations with external services for potential credential exposure vulnerabilities.

Attack Surface: ProcessHandler Vulnerabilities

Description: Using ProcessHandler to execute external commands based on log events introduces critical command injection and privilege escalation risks due to the nature of executing arbitrary commands.

Monolog Contribution: ProcessHandler directly enables the execution of arbitrary commands when a log event occurs, making it a high-risk feature if misused or misconfigured.

Example:

• Command Injection: If the command executed by ProcessHandler is even partially constructed using log message data or any external input (extremely dangerous and discouraged), an attacker can inject arbitrary commands.
• Privilege Escalation: If the command executed by ProcessHandler is configured to run with elevated privileges (e.g., via sudo or running the application as root), vulnerabilities in the executed command or attacker-controlled input could lead to privilege escalation.

Impact:

• Command Injection: Arbitrary code execution, system compromise.
• Privilege Escalation: Full system compromise, unauthorized access.

Risk Severity: Critical

Mitigation Strategies:

• Avoid ProcessHandler if possible: The most effective mitigation is to avoid using ProcessHandler altogether due to its inherent risks. Explore alternative logging mechanisms that do not involve executing external commands.
• Never use user-controlled input in commands: If ProcessHandler must be used, ensure the command executed is absolutely static and hardcoded within the configuration. Never incorporate any log message content or external data into the command string.
• Principle of Least Privilege (Process Execution): Configure ProcessHandler to execute commands with the minimum necessary privileges. Never run commands as root or with elevated privileges unless absolutely unavoidable and after extremely careful security review.
• Security Audits and Code Reviews: Thoroughly audit and review any code that uses ProcessHandler. Security reviews should be mandatory before deploying any application using ProcessHandler. Consider code scanning tools to detect potential command injection vulnerabilities.