mcp-memory-service Vulnerable to System Information Disclosure via Health Endpoint

Summary

The /api/health/detailed endpoint returns detailed system information including OS version, Python version, CPU count, memory totals, disk usage, and the full database filesystem path. When MCP_ALLOW_ANONYMOUS_ACCESS=true is set (required for the HTTP server to function without OAuth/API key), this endpoint is accessible without authentication. Combined with the default 0.0.0.0 binding, this exposes sensitive reconnaissance data to the entire network.

Details

Vulnerable Code

health.py:90-101 - System information collection

system_info = {
    "platform": platform.system(),              # e.g., "Linux", "Darwin"
    "platform_version": platform.version(),     # Full OS kernel version string
    "python_version": platform.python_version(),# e.g., "3.12.1"
    "cpu_count": psutil.cpu_count(),            # CPU core count
    "memory_total_gb": round(memory_info.total / (1024**3), 2),
    "memory_available_gb": round(memory_info.available / (1024**3), 2),
    "memory_percent": memory_info.percent,
    "disk_total_gb": round(disk_info.total / (1024**3), 2),
    "disk_free_gb": round(disk_info.free / (1024**3), 2),
    "disk_percent": round((disk_info.used / disk_info.total) * 100, 2)
}

health.py:131-132 - Database path disclosure

if hasattr(storage, 'db_path'):
    storage_info["database_path"] = storage.db_path  # Full filesystem path

Authentication Bypass Path

The /api/health/detailed endpoint uses require_read_access which calls get_current_user. When MCP_ALLOW_ANONYMOUS_ACCESS=true, the auth middleware grants access:

# middleware.py:372-379
if ALLOW_ANONYMOUS_ACCESS:
    logger.debug("Anonymous access explicitly enabled, granting read-only access")
    return AuthenticationResult(
        authenticated=True,
        client_id="anonymous",
        scope="read",
        auth_method="none"
    )

Note: The basic /health endpoint (line 68) has no auth dependency at all and returns version and uptime information unconditionally.

Information Exposed

Field	Example Value	Reconnaissance Value
platform	"Linux"	OS fingerprinting
platform_version	"#1 SMP PREEMPT_DYNAMIC..."	Kernel version → CVE targeting
python_version	"3.12.1"	Python CVE targeting
cpu_count	8	Resource enumeration
memory_total_gb	32.0	Infrastructure profiling
database_path	"/home/user/.mcp-memory/memories.db"	Username + file path disclosure
database_size_mb	45.2	Data volume estimation

Attack Scenario

1. Attacker scans the local network for services on port 8000
2. Finds mcp-memory-service with HTTP enabled and anonymous access
3. Calls GET /api/health/detailed (no credentials needed)
4. Receives OS version, Python version, full database path (revealing username), system resources
5. Uses this information to:
   • Target known CVEs for the specific OS/Python version
   • Identify the database file location for potential direct access
   • Profile the system for further attacks

PoC

# Show the system info that would be exposed
import platform, psutil

system_info = {
    "platform": platform.system(),
    "platform_version": platform.version(),
    "python_version": platform.python_version(),
    "cpu_count": psutil.cpu_count(),
    "memory_total_gb": round(psutil.virtual_memory().total / (1024**3), 2),
}
print(system_info)  # All of this is returned to unauthenticated users

Impact

• OS fingerprinting: Exact OS and kernel version enables targeted exploit selection
• Path disclosure: Database path reveals username, home directory structure, and file locations
• Resource enumeration: CPU, memory, and disk info reveal infrastructure scale
• Reconnaissance enablement: Combined information significantly reduces attacker effort for follow-up attacks

Remediation

1. Remove system details from default health endpoint - return only status, version, uptime:

@router.get("/health/detailed")
async def detailed_health_check(
    storage: MemoryStorage = Depends(get_storage),
    user: AuthenticationResult = Depends(require_write_access)  # Require admin/write access
):
    # Only return storage stats, not system info
    ...

2. Do not expose database_path - this leaks the filesystem structure:

# Remove or redact
# storage_info["database_path"] = storage.db_path  # REMOVE THIS

3. Add auth to basic /health or limit it to status-only (no version):

@router.get("/health")
async def health_check():
    return {"status": "healthy"}  # No version, no uptime

Alternatively, Bind to 127.0.0.1 by default instead of 0.0.0.0, preventing network-based reconnaissance entirely:

# In config.py — change default from '0.0.0.0' to '127.0.0.1'
HTTP_HOST = os.getenv('MCP_HTTP_HOST', '127.0.0.1')

Users who need network access can explicitly set MCP_HTTP_HOST=0.0.0.0, making the exposure a conscious opt-in rather than a default.