attack-surface.md

Attack Surface Analysis for gabime/spdlog

Attack Surface: Denial of Service (DoS) via Log Flooding

• Description: An attacker overwhelms the logging system with a high volume of log messages, causing resource exhaustion (disk space, CPU, I/O, memory).
• spdlog Contribution: spdlog provides the core logging mechanisms (sinks, formatters, asynchronous queues) that are directly involved in handling the flood of messages. The asynchronous queue, while designed for performance, has a finite capacity and can become a bottleneck or overflow. The choice of sink and its performance characteristics directly impact the severity.
• Example: An attacker exploits a vulnerability in the application to trigger numerous error messages. spdlog, configured to use an asynchronous logger with a blocking overflow policy, becomes overwhelmed. The application threads waiting to log become blocked, leading to application unresponsiveness.
• Impact: Application slowdown or complete unresponsiveness. Potential data loss if the asynchronous queue overflows and the policy is set to discard. Disk space exhaustion.
• Risk Severity: High
• Mitigation Strategies:
  • Bounded Asynchronous Queue: Use a bounded queue for asynchronous logging and monitor its size. Carefully choose the overflow policy (block or discard) based on application requirements. block is the default and can lead to DoS.
  • Efficient Sinks: Select efficient sinks appropriate for the expected log volume. Avoid slow sinks (e.g., network sinks over a congested connection) if high-volume logging is anticipated.
  • Alerting: Configure alerts for high log volume, queue overflow, or excessive disk space usage related to spdlog's output.

Attack Surface: Code Injection (Highly Unlikely)

• Description: A vulnerability in spdlog's formatting or parsing logic, specifically within spdlog's own code or the fmt library it uses, is exploited to inject and execute arbitrary code. This excludes vulnerabilities in custom formatters written by application developers.
• spdlog Contribution: spdlog's internal code, including its use of the fmt library for formatting, is the direct target of this attack. The vulnerability would need to exist within spdlog or fmt itself.
• Example: A hypothetical zero-day vulnerability in spdlog's pattern parsing logic allows an attacker to craft a malicious log message that, when processed by spdlog, triggers arbitrary code execution. This is not a vulnerability in a custom formatter, but in spdlog's core code.
• Impact: Complete system compromise.
• Risk Severity: Critical (but extremely low probability)
• Mitigation Strategies:
  • Keep spdlog and fmt Updated: This is the primary mitigation. Regularly update spdlog and the fmt library to the latest versions to receive security patches. This addresses vulnerabilities discovered in the library itself.
  • Principle of Least Privilege: Run the application with the minimum necessary privileges. This limits the damage a successful code injection attack can cause, even if spdlog is compromised.