security-review-architecture

Security Review Architecture: WinShut

Target: WinShut v1.0.6 - Remote Windows Power Management over HTTPS
Review Type: Full Adversarial Security Review
Reviewer: Winston (Architect) + Craig
Date: 2026-02-26

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Executive Summary

WinShut is a Go-based HTTPS service that exposes Windows power management functions (shutdown, restart, hibernate, sleep, lock, logoff, screen-off) over a network API. It runs as a Windows SYSTEM service and claims to use mTLS for authentication.

Critical Concern: Network-exposed privileged operations running at SYSTEM level present a high-value attack target. Any authentication bypass, privilege escalation, or DoS vulnerability could have severe impact.

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1. System Overview

1.1 Architecture

[Client] --mTLS--> [HTTPS Server :9090] --> [Windows Power APIs]
    |                    |                         |
 client.crt          auth.go                 power_windows.go
                  handlers.go              service_windows.go
                 ratelimit.go

1.2 Technology Stack

• Language: Go
• Platform: Windows (with stub implementations for dev)
• Transport: HTTPS with mTLS
• Authentication: X.509 client certificates
• Privilege: SYSTEM service
• External Dependencies: Go stdlib + minimal deps (analyze go.mod)

1.3 Attack Surface

Component	Exposure	Privilege	Risk
HTTPS Server	Network	SYSTEM	CRITICAL
mTLS Auth	Certificate-based	SYSTEM	HIGH
Power APIs	System calls	SYSTEM	HIGH
Certificate Generation	Local filesystem	User/Admin	MEDIUM
Rate Limiting	Memory-based	SYSTEM	MEDIUM
Windows Service	Service Control Manager	SYSTEM	MEDIUM

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2. Threat Model (STRIDE Analysis)

2.1 Spoofing Identity

• Threat: Attacker obtains or forges client certificate
• Attack Vectors:
  • Weak certificate generation (predictable keys, weak entropy)
  • Certificate theft from client machines
  • CA private key compromise
  • Certificate validation bypass in mTLS implementation

2.2 Tampering with Data

• Threat: Attacker modifies requests in transit or at rest
• Attack Vectors:
  • TLS downgrade attacks
  • Certificate pinning bypass
  • Request smuggling/manipulation

2.3 Repudiation

• Threat: Actions performed cannot be traced to attacker
• Attack Vectors:
  • Missing or insufficient logging
  • Log tampering (SYSTEM privilege)
  • No audit trail for power operations

2.4 Information Disclosure

• Threat: Sensitive information leaked
• Attack Vectors:
  • /stats endpoint leaking system information
  • Error messages revealing internal paths/structure
  • Certificate material exposure
  • Timing attacks on authentication

2.5 Denial of Service

• Threat: Service or system availability impacted
• Attack Vectors:
  • Rate limiting bypass
  • Resource exhaustion (memory, CPU, connections)
  • Repeated shutdown/restart commands
  • Certificate validation DoS

2.6 Elevation of Privilege

• Threat: Lower-privileged attacker gains SYSTEM access
• Attack Vectors:
  • Authentication bypass → SYSTEM command execution
  • Path traversal in certificate loading
  • DLL hijacking in service context
  • Race conditions in privilege checks

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3. Security Review Methodology

3.1 Phase 1: Code Reconnaissance (CURRENT)

Objective: Map the complete attack surface and identify high-risk areas

Tasks:

• Analyze repository structure and identify all entry points
• Review authentication implementation (auth.go)
• Analyze HTTP handlers and input validation (handlers.go)
• Examine rate limiting implementation (ratelimit.go)
• Study certificate generation and validation
• Review Windows-specific power APIs (power_windows.go)
• Analyze Windows service implementation (service_windows.go)
• Dependency audit (go.mod, go.sum)

3.2 Phase 2: Adversarial Analysis

Objective: Find exploitable vulnerabilities with attacker mindset

Attack Scenarios:

1. Authentication Bypass: Can we access endpoints without valid certs?
2. Certificate Forgery: Can we create valid certificates?
3. Privilege Escalation: Can we execute arbitrary commands via power APIs?
4. Denial of Service: Can we crash the service or the system?
5. Information Disclosure: Can we extract sensitive data?
6. Race Conditions: Can we exploit timing windows?

3.3 Phase 3: Vulnerability Validation

Objective: Confirm exploitability and impact

Methods:

• Static code analysis (manual review)
• Pattern matching for common Go vulnerabilities
• Crypto implementation review
• Logic flaw identification
• Edge case testing scenarios

3.4 Phase 4: Risk Scoring & Reporting

Objective: Prioritize findings and provide actionable recommendations

Severity Matrix:

• CRITICAL: Remote code execution, authentication bypass, system compromise
• HIGH: Privilege escalation, DoS leading to system crash, sensitive data exposure
• MEDIUM: DoS without crash, information leakage, weak crypto
• LOW: Information disclosure (minimal), configuration issues

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4. Specific Areas of Investigation

4.1 Authentication & Authorization (auth.go)

Questions:

• How is mTLS certificate validation implemented?
• Are there any bypass conditions (error handling, edge cases)?
• Is the CA certificate properly validated?
• Can an expired or revoked certificate still authenticate?
• What happens with self-signed certificates?
• Is certificate CN/SAN properly checked?

Attack Vectors:

// Potential issues to look for:
- Empty certificate chain handling
- Nil pointer dereferences in cert validation
- Improper error handling allowing fallthrough
- Time-based validation bypass (expired certs)

4.2 HTTP Handlers (handlers.go)

Questions:

• Is there input validation on all endpoints?
• Are there any unauthenticated endpoints besides /health?
• Can we trigger unexpected behavior with malformed requests?
• Are there any command injection vectors?
• How are errors handled and returned to clients?

Attack Vectors:

// Potential issues:
- Missing authentication checks on critical endpoints
- Panic conditions leading to service crash
- Path traversal in any file operations
- Header injection vulnerabilities

4.3 Rate Limiting (ratelimit.go)

Questions:

• Is rate limiting per-IP, per-certificate, or global?
• Can rate limits be bypassed with multiple IPs or certificates?
• What happens when rate limit is exceeded?
• Is there a resource exhaustion vector via rate limiter itself?
• Are rate limit counters thread-safe?

Attack Vectors:

// Potential issues:
- Race conditions in counter increments
- Memory exhaustion via limiter state
- Bypass via connection pooling
- Reset conditions allowing abuse

4.4 Certificate Generation (Makefile + openssl commands)

Questions:

• Is the certificate generation process secure?
• Are private keys generated with sufficient entropy?
• Are key permissions properly set?
• Can an attacker predict generated keys?
• Is the CA key properly protected?

Attack Vectors:

# Potential issues:
- Weak PRNG usage
- Insufficient key length
- Poor file permissions on private keys
- CA key left on target systems

4.5 Power Management APIs (power_windows.go)

Questions:

• Are Windows API calls properly sanitized?
• Can we pass unexpected parameters?
• Are there any buffer overflow risks in Windows syscalls?
• Can we trigger unintended system behavior?
• Are power operations properly logged?

Attack Vectors:

// Potential issues:
- Improper syscall parameter handling
- Missing privilege checks before operations
- Race conditions in power state transitions
- Unchecked error codes from Windows APIs

4.6 Windows Service (service_windows.go)

Questions:

• How is the service installed and configured?
• Are command-line arguments properly sanitized?
• Can we inject malicious paths during installation?
• Is the service recovery configuration secure?
• Are credentials properly protected in service config?

Attack Vectors:

// Potential issues:
- Command injection via service install args
- Path traversal in certificate paths
- DLL search order hijacking
- Service recovery exploitation

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5. Adversarial Testing Plan

5.1 Black Box Testing (Assume No Code Access)

1. Port Scanning: Identify exposed services
2. Certificate Testing: Try invalid/expired/self-signed certs
3. Endpoint Fuzzing: Test all API endpoints with malformed data
4. Rate Limit Testing: Attempt to bypass or exhaust rate limiting
5. DoS Testing: Flood endpoints, send large requests
6. Information Gathering: Extract version info, system details

5.2 White Box Testing (With Code Access - CURRENT MODE)

1. Code Review: Line-by-line analysis of critical components
2. Crypto Review: Validate TLS configuration and cert handling
3. Logic Flaw Analysis: Find business logic vulnerabilities
4. Race Condition Analysis: Identify concurrency issues
5. Dependency Audit: Check for known CVEs in dependencies

5.3 Gray Box Testing (Partial Knowledge)

1. Configuration Testing: Test with various config permutations
2. Error Injection: Trigger error conditions, observe behavior
3. Timing Analysis: Measure response times for auth bypass detection

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6. Expected Findings (Hypothesis)

Based on initial reconnaissance, we anticipate finding:

6.1 High Probability Issues

1. Weak Rate Limiting: In-memory rate limiting likely bypassable
2. Insufficient Logging: SYSTEM service may not log power operations adequately
3. Certificate Handling: Edge cases in mTLS validation
4. Error Information Disclosure: Verbose error messages revealing internal state
5. Configuration Issues: Weak default settings or insecure examples

6.2 Medium Probability Issues

1. Authentication Bypass: Logic flaws in certificate validation
2. Race Conditions: Concurrent request handling issues
3. Resource Exhaustion: Memory or connection leaks
4. Path Traversal: Certificate or log file path handling

6.3 Low Probability Issues (But High Impact)

1. Remote Code Execution: Via command injection or buffer overflow
2. Privilege Escalation: Beyond SYSTEM (unlikely, but check)
3. Cryptographic Flaws: Weak key generation or TLS downgrade

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7. Risk Assessment Framework

7.1 Impact Scoring

Impact Level	Description	Score
CRITICAL	System compromise, arbitrary code execution	5
HIGH	Service compromise, DoS with system crash	4
MEDIUM	Service DoS, sensitive data exposure	3
LOW	Information leakage, configuration issues	2
INFO	Best practice violations, no direct exploit	1

7.2 Exploitability Scoring

Difficulty	Description	Score
TRIVIAL	Public exploit available, no auth required	5
EASY	Requires valid cert, straightforward exploit	4
MODERATE	Requires specific conditions or timing	3
DIFFICULT	Requires rare conditions or deep knowledge	2
THEORETICAL	Possible but impractical to exploit	1

7.3 Overall Risk

Risk Score = Impact × Exploitability

• 20-25: CRITICAL - Immediate action required
• 12-16: HIGH - Fix before production use
• 6-9: MEDIUM - Address in next release
• 2-4: LOW - Track for future improvement
• 1: INFO - Document and monitor

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8. Tools & Resources

8.1 Static Analysis Tools

• go vet - Built-in Go static analyzer
• staticcheck - Go linter
• gosec - Go security checker
• Manual code review (primary method)

8.2 Dependency Analysis

• go mod graph - Dependency tree
• govulncheck - Known vulnerability scanner
• CVE databases for external deps

8.3 Reference Materials

• OWASP Top 10
• CWE Top 25
• Go security best practices
• Windows service security guidelines
• TLS/mTLS security standards

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9. Deliverables

1. This Document: Security Review Architecture (COMPLETE)
2. Vulnerability Report: Detailed findings with PoCs
3. Risk Matrix: Prioritized vulnerabilities
4. Remediation Recommendations: Specific, actionable fixes
5. Code Examples: Secure implementation patterns

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10. Next Steps

READY TO BEGIN ADVERSARIAL ANALYSIS

We will now systematically review each component identified in the attack surface, starting with the highest-risk areas:

1. First Target: Authentication (auth.go) - Can we bypass mTLS?
2. Second Target: Handlers (handlers.go) - Can we exploit endpoints?
3. Third Target: Rate Limiting (ratelimit.go) - Can we DoS the service?
4. Fourth Target: Certificate Management - Can we forge certs?
5. Fifth Target: Windows APIs - Can we escalate or inject?

Current Status: Architecture and methodology defined. Ready for Phase 2: Adversarial Analysis.

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This document serves as the technical blueprint for conducting a comprehensive, adversarial security review of WinShut. All findings will be documented with severity, exploitability, and remediation guidance.