Insertion of Sensitive Information into Log File

Description

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the following code snippet, a user's full name and credit card number are written to a log file.

logger.info("Username: " + usernme + ", CCN: " + ccn);

Example Two

This code stores location information about the current user:

locationClient = new LocationClient(this, this, this);
locationClient.connect();
currentUser.setLocation(locationClient.getLastLocation());
...

catch (Exception e) {
  AlertDialog.Builder builder = new AlertDialog.Builder(this);
  builder.setMessage("Sorry, this application has experienced an error.");
  AlertDialog alert = builder.create();
  alert.show();
  Log.e("ExampleActivity", "Caught exception: " + e + " While on User:" + User.toString());
}

When the application encounters an exception it will write the user object to the log. Because the user object contains location information, the user's location is also written to the log.

Example Three

In the example below, the method getUserBankAccount retrieves a bank account object from a database using the supplied username and account number to query the database. If an SQLException is raised when querying the database, an error message is created and output to a log file.

public BankAccount getUserBankAccount(String username, String accountNumber) {

  BankAccount userAccount = null;
  String query = null;
  try {
    if (isAuthorizedUser(username)) {
      query = "SELECT * FROM accounts WHERE owner = "
      + username + " AND accountID = " + accountNumber;
      DatabaseManager dbManager = new DatabaseManager();
      Connection conn = dbManager.getConnection();
      Statement stmt = conn.createStatement();
      ResultSet queryResult = stmt.executeQuery(query);
      userAccount = (BankAccount)queryResult.getObject(accountNumber);
    }
  } catch (SQLException ex) {
    String logMessage = "Unable to retrieve account information from database,\nquery: " + query;
    Logger.getLogger(BankManager.class.getName()).log(Level.SEVERE, logMessage, ex);
  }
  return userAccount;

}

The error message that is created includes information about the database query that may contain sensitive information about the database or query logic. In this case, the error message will expose the table name and column names used in the database. This data could be used to simplify other attacks, such as SQL injection (CWE-89) to directly access the database.

See Also