Configuration files play a critical role in storing sensitive credentials for various applications and services. Attackers often target these files to extract valuable information, such as usernames, passwords, API keys, and database credentials. Understanding the techniques employed by adversaries is vital in implementing effective defensive measures.

Techniques for Extracting Credentials

Attackers utilize multiple methods to extract credentials from configuration files. The following techniques are commonly observed in credential extraction attacks:

  • File Parsing: Attackers parse configuration files, leveraging knowledge of file formats and patterns to identify and extract credentials.
  • Regular Expressions: Utilizing pattern matching techniques, attackers search for credential-like strings within configuration files.
  • File Inclusion Vulnerabilities: Exploiting vulnerabilities that allow them to read or include arbitrary files, attackers gain access to configuration files containing credentials.
  • Data Leakage: Identifying misconfigurations or insecure logging practices, attackers exploit logs or error messages that inadvertently reveal credentials.

Common Configuration Files Containing Credentials

Certain configuration files frequently store credentials, making them attractive targets for attackers. Examples of commonly targeted files include:

  • Web Application Configurations: Files like web.config (ASP.NET), .env (PHP), or application.properties (Java) may contain database credentials or API keys.
  • Database Configuration Files: Configuration files like my.cnf (MySQL) or pg_hba.conf (PostgreSQL) often store database access credentials.
  • Network Service Configurations: SSH server configurations (sshd_config), mail server configurations (smtpd.conf), or VPN configurations (openvpn.conf) may contain critical credentials.
  • Binary Analysis: Attackers analyze binary files associated with applications to extract credentials embedded within them.
  • Memory Scraping: Attackers target running processes or system memory to retrieve credentials stored temporarily during application runtime.
  • Configuration File Misplacement: Attackers exploit misconfigurations that result in configuration files being inadvertently placed in publicly accessible locations.
  • Server Misconfigurations: Attackers leverage misconfigurations in web servers, FTP servers, or other services to gain unauthorized access to configuration files and extract credentials.

Example

1. In this case we have an application installed, which is connected to a database, looking into the configuration files we found config.json, which contains a username and password. The first step is to identify the home folder for the application

  • whereis mattermost

2. Knowing this help us find files using different techniques

  • ls -lR | grep -i conf
  • find /opt/mattermost -type f -iname "*config*" -o -iname "*conf*" 2> /dev/null
  • find /opt/mattermost -type f -exec grep -liE 'username|password|user|pass' {} +

3. Searching though the output we found config.json, reading this file we can find

  • cat /opt/mattermost/config/config.json | grep -iE "user|username|pass|password"

4. Knowing, this configuration file could contain additional information, we proceed to read it

  • cat /opt/mattermost/config/config.json | less

Note: we also found something that seems SQL username and password

5. We will try access this database

  • mysql -u mmuser -p
  • Password: Crack_The_MM_Admin_PW
  • show databases;

Countermeasures: Protecting Credentials in Configuration Files

To mitigate the risk of credential extraction from configuration files, the following countermeasures should be implemented:

  • Encryption and Hashing: Encrypt or hash sensitive credentials within configuration files to make them unusable if obtained by attackers.
  • Secure File Permissions: Set appropriate file permissions to limit access to configuration files, ensuring that only authorized users can read or modify them.
  • Environment Variables: Store credentials as environment variables instead of hardcoding them in configuration files.
  • Credential Management Systems: Implement secure credential management systems that centralize and protect sensitive credentials.
  • Regular Auditing: Conduct regular audits to identify insecure configurations and ensure proper protection of credentials.
  • Secure Development Practices: Train developers on secure coding practices, emphasizing the importance of properly handling credentials in configuration files.

Monitoring and Intrusion Detection

Implementing robust monitoring and intrusion detection mechanisms can help identify unauthorized access or suspicious activities related to configuration files. Key monitoring measures include:

  • Log Monitoring: Regularly analyze logs for unusual activity, such as unexpected modifications or access to configuration files.
  • Intrusion Detection Systems (IDS): Deploy IDS solutions to detect anomalous patterns or known attack signatures targeting configuration files.
  • Endpoint Security: Employ endpoint security solutions that detect and prevent unauthorized access to configuration files.