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OpenWeatherMap API Key

An OpenWeatherMap API Key is a credential used to authenticate requests to the OpenWeatherMap service, which provides weather data for various locations worldwide. This API key allows applications to access current weather data, forecasts, and historical weather data. Exposure of this API key is a security concern because it can lead to unauthorized use of the service, potentially resulting in unexpected charges or service disruptions.

How Does It Look​

OpenWeatherMap API keys can appear in various contexts, such as:

  • Environment variables:

    export OPENWEATHERMAP_API_KEY="abcd1234efgh5678ijkl9012mnop3456"

  • Configuration files (JSON, YAML, .env):

    {
      "apiKey": "abcd1234efgh5678ijkl9012mnop3456"
    }
    api_key: abcd1234efgh5678ijkl9012mnop3456
    OPENWEATHERMAP_API_KEY=abcd1234efgh5678ijkl9012mnop3456

  • Code snippets:

    api_key = "abcd1234efgh5678ijkl9012mnop3456"

Severity​

  • 🟡 Medium

The severity of an OpenWeatherMap API key exposure is considered medium because it primarily allows access to weather data, which is generally not sensitive. However, unauthorized use can lead to increased API usage costs and potential service disruptions if rate limits are exceeded.

What Can an Attacker Do?​

With immediate access to an exposed OpenWeatherMap API key, an attacker can:

  • Access weather data: Retrieve current weather, forecasts, and historical data (if the API key has the necessary permissions).
  • Exceed rate limits: Make excessive requests, potentially leading to service disruptions or additional charges (if the account is billed based on usage).
  • Consume API quota: Use up the allocated API requests, preventing legitimate users from accessing the service (if the API key has limited requests).

While the immediate impact is limited to data access and potential financial costs, an attacker could use the API key to perform denial-of-service attacks by exhausting the API quota, affecting the availability of weather data for legitimate users.

Real-World Impact​

The exposure of an OpenWeatherMap API key poses several business risks:

  • Data Exposure: Access to weather data (if the credential has read access to sensitive data).
  • Financial Loss: Increased costs due to unauthorized API usage (if billing/resource creation is permitted).
  • Operational Disruption: Service interruptions due to exceeded rate limits (if the attacker has excessive usage permissions).
  • Reputational Damage: Loss of trust if users experience service disruptions.

While the primary impact is financial and operational, cascading effects could include customer dissatisfaction and potential loss of business if service disruptions persist.

Prerequisites for Exploitation​

To exploit an exposed OpenWeatherMap API key, an attacker needs:

  • Network access: Ability to send requests to the OpenWeatherMap API endpoints.
  • API endpoint knowledge: Understanding of the OpenWeatherMap API structure and endpoints.
  • No rate limits: Exploitation is easier if the API key is not subject to strict rate limits.

How to Verify If It's Active​

To verify if an OpenWeatherMap API key is active, use the following command:

curl -X GET "http://api.openweathermap.org/data/2.5/weather?q=London&appid=[API_KEY]"

Valid credential response: A successful response will include weather data for the specified location, such as temperature, humidity, and weather conditions.

Invalid/expired credential response: An error message indicating an invalid API key or unauthorized access.

Detection Patterns​

Common Variable Names:

  • OPENWEATHERMAP_API_KEY
  • WEATHER_API_KEY
  • OWM_API_KEY
  • API_KEY
  • WEATHER_KEY
  • OWM_KEY

File Locations:

  • .env
  • config.json
  • settings.yaml
  • weather_config.py
  • application.properties

Regex Pattern:

[a-zA-Z0-9]{32}

Remediation Steps​

  1. Revoke immediately - Go to OpenWeatherMap account settings and regenerate the API key.
  2. Audit access logs - Review OpenWeatherMap usage logs for unauthorized requests during the exposure window.
  3. Assess blast radius - Identify all systems, applications, and environments that used the exposed API key.
  4. Rotate credential - Generate a new API key in OpenWeatherMap and update all dependent systems.
  5. Update dependent systems - Deploy the new API key to all applications and update CI/CD pipelines securely.
  6. Harden access controls - Enable IP allowlisting in OpenWeatherMap and set strict rate limits.
  7. Implement secrets management - Migrate API keys to a secrets manager (HashiCorp Vault, AWS Secrets Manager) to prevent hardcoding.
  8. Add detection controls - Set up pre-commit hooks and repository scanning to catch credential leaks before they reach production.

Credential exposures often go undetected for extended periods, increasing the window for exploitation. As a long-term strategy, plan to establish an internal process or engage an external vendor for continuous external exposure monitoring. This helps identify leaked secrets across public repositories, paste sites, dark web forums, and other external sources before attackers can leverage them. Proactive detection and rapid response are essential to minimizing the impact of credential leaks.

References​