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Security audit

Weather NWS

Security checks for vulnerabilities and agentic risk

Overview

This weather skill uses external weather and geocoding services as expected, with an optional AirNow API key, and I found no hidden persistence, prompt hijacking, destructive behavior, or unrelated data access.

Install only if you are comfortable sending weather locations, including precise addresses or ZIP codes if you enter them, to external services. Configure AIRNOW_API_KEY only if you want AQI data and are comfortable with that key being used in AirNow API requests.

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
  • Unauthorized Access and Privilege EscalationObtains permissions beyond the task's legitimate needs
Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
  • MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Findings (13)

Tp4

High
Category
MCP Tool Poisoning
Confidence
95% confidence
Finding

The declared purpose focuses on weather forecasting, but the skill also advertises AQI retrieval, astronomical calculations, aviation forecasts, and fire weather handling. This mismatch weakens informed consent and reviewability because operators may approve the skill for one purpose while it performs additional networked behaviors and processes extra categories of user queries.

Content

No source excerpt is available for this finding.

Undeclared Tool Scope

Medium
Category
MCP Least Privilege
Confidence
92% confidence
Finding

The skill documentation indicates it uses environment variables and network access, but it does not declare any explicit tool scope such as permissions or allowed-tools. That creates an authorization gap where the runtime may grant broader capabilities than users or the platform expect, reducing transparency and making abuse harder to constrain.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

The manifest describes a weather skill focused on US forecasts, accumulation data, warnings, and global fallback, but the module documentation explicitly adds aviation TAFs and fire weather as Phase 3 capabilities. Those specialized domains are not mentioned in the manifest description or intended-use text, so the implemented feature set exceeds the declared behavior.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

User-supplied location queries are sent to third-party services (Nominatim and later wttr.in/NWS) without any visible user consent or disclosure mechanism in the skill. Because location data can be sensitive, especially precise addresses or ZIP codes, this creates a privacy risk through external transmission beyond the local agent environment.

Content

No source excerpt is available for this finding.

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 4)May include surrounding context.

md
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/get_weather.py (reported line 214)May include surrounding context.

python
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/get_weather.py (reported line 251)May include surrounding context.

python
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/get_weather.py (reported line 292)May include surrounding context.

python
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/get_weather.py (reported line 331)May include surrounding context.

python
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/get_weather.py (reported line 568)May include surrounding context.

python
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/get_weather.py (reported line 667)May include surrounding context.

python
def get_nws_gridpoint(lat, lon):
    """Get NWS gridpoint for lat/lon"""
    try:
        url = f"https://api.weather.gov/points/{lat},{lon}"
        req = urllib.request.Request(url, headers={'User-Agent': 'ClawdWeather/1.0'})
        
        with urllib.request.urlopen(req, timeout=10) as response:

Missing User Warnings

Low
Category
Not specified by scanner
Confidence
91% confidence
Finding

The code accesses a sensitive environment variable, AIRNOW_API_KEY, and appends it to outbound HTTP requests. Although this is functionally expected for API usage, the file contains no visible warning in help text, comments for users, or other user-facing disclosure that a credential is consumed and sent to an external service.

Content

No source excerpt is available for this finding.

Context-Inappropriate Capability

Low
Category
Not specified by scanner
Confidence
83% confidence
Finding

The code accesses AIRNOW_API_KEY from environment variables to call a third-party air-quality API. While AQI support is documented in code, credential access is a broader capability than a straightforward public weather fetcher and is not justified by the manifest text, which does not mention secret handling or credentialed integrations.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.