Attack Surface: Code Injection into Compilation
- Description: An attacker injects malicious C# or VB.NET code into the source code that Roslyn compiles, leading to arbitrary code execution.
- Roslyn Contribution: Roslyn's core function is to compile code; this inherent capability is the attack vector. Roslyn directly executes the injected code upon compilation.
- Example:
- A web application allows users to enter C# code snippets for "live evaluation." An attacker submits code that downloads and executes a malware payload.
- An application uses Roslyn to generate code based on user-provided templates. The attacker injects malicious code into the template.
- Impact: Complete system compromise; data theft; malware installation; denial of service.
- Risk Severity: Critical
- Mitigation Strategies:
- Strict Input Validation: Implement rigorous validation of all input used in code generation. Reject any input that contains unexpected characters, keywords, or patterns. Prefer allow-listing (whitelisting).
- Sandboxing: Execute the compiled code in a highly restricted environment (container, VM). This limits the damage even if code execution occurs.
- Avoid Dynamic Compilation (if possible): If functionality can be achieved without dynamic compilation, choose that approach.
- Template Engine Security: If using a template engine, ensure it's secure and user input is properly escaped within the template.
- Code Signing (Post-Compilation): Digitally sign the compiled assembly to detect tampering after compilation.
- Allow Lists (Whitelisting): Define a strict allow list of permitted code constructs, libraries, and APIs.
Attack Surface: Denial of Service (DoS) via Compilation
- Description: An attacker submits excessively large or complex code to Roslyn, causing resource exhaustion (CPU, memory, disk) and denial of service.
- Roslyn Contribution: Roslyn's compilation process is resource-intensive; this is exploited to cause DoS. Roslyn directly consumes the resources during the compilation attempt.
- Example:
- An attacker submits a C# script with deeply nested loops or a large number of classes, causing the compilation process to consume all available memory.
- An attacker repeatedly submits code for compilation, overwhelming the server.
- Impact: Application unavailability; service disruption.
- Risk Severity: High
- Mitigation Strategies:
- Resource Limits: Impose strict limits on code size, complexity (e.g., nesting depth), and compilation time.
- Rate Limiting: Limit the frequency of compilation requests.
- Asynchronous Compilation: Compile code in a background process.
- Queueing: Use a queue to manage compilation requests.
- Input Size Limits: Enforce maximum input size limits.
Attack Surface: Vulnerabilities in Roslyn Itself
- Description: Exploitation of vulnerabilities within the Roslyn library itself.
- Roslyn Contribution: Roslyn, like any software, may contain vulnerabilities. The vulnerability is directly within the Roslyn codebase.
- Example: A buffer overflow vulnerability in Roslyn's parsing logic is exploited by providing specially crafted code.
- Impact: Varies; could range from denial of service to arbitrary code execution.
- Risk Severity: High (Potentially Critical, depending on the vulnerability)
- Mitigation Strategies:
- Keep Roslyn Updated: Regularly update to the latest version of Roslyn.
- Monitor Security Advisories: Stay informed about Roslyn security advisories.
- Defense in Depth: Implement multiple layers of security.