MSC31-C. Never hard code sensitive information

Hard coding sensitive information, such as passwords or encryption keys can expose the information to attackers. Anyone who has access to the executable or dynamic library files can examine them for strings or other critical data, revealing the sensitive information. Leaking data protected by International Traffic in Arms Regulations (ITAR) or the Health Insurance Portability and Accountability Act (HIPAA) can also have legal consequences. Consequently, programs must not hard code sensitive information.

Hard coding sensitive information also increases the need to manage and accommodate changes to the code. For example, changing a hard-coded password in a deployed program may require distribution of a patch [Chess 2007].

Noncompliant Code Example (Hard-Coded Database Password)

The user name and password fields in the SQL connection request are hard coded in this noncompliant code example:

/* Returns nonzero if authenticated */
int authenticate(const char* code);

int main() {
  if (!authenticate("correct code")) {
    printf("Authentication error\n");
    return -1;
  }

  printf("Authentication successful\n");
  // ...Work with system...
  return 0;
}

Note that the one- and two-argument java.sql.DriverManager.getConnection() methods can also be used incorrectly.

% strings a.out
...
AUATL
[]A\A]A^A_
correct code
Authentication error
Authentication successful
...
%

Compliant Solution

This compliant solution reads the user name and password from a configuration file located in a secure directory:

/* Returns nonzero if authenticated */
int authenticate(const char* code);

int main() {
#define CODE_LEN 50
  char code[CODE_LEN];
  printf("Please enter your authentication code:\n");
  fgets(code, sizeof(code), stdin);
  int flag = authenticate(code);
  memset_s(code, 0, sizeof(code));
  if (!flag) {
    printf("Access denied\n");
    return -1;
  }
  printf("Access granted\n");
  // ...Work with system...
  return 0;
}

It is also permissible to prompt the user for the user name and password at runtime.

When possible, sensitive information such as passwords should be stored in character arrays rather than strings because the Java Virtual Machine may retain strings long after they are no longer needed. However, this example uses strings because DriverManager.getConnection() requires them.

Risk Assessment

Hard coding sensitive information exposes that information to attackers. The severity of this rule can vary depending on the kind of information that is disclosed. Frequently, the information disclosed is password or key information, which can lead to remote exploitation. Consequently, a high severity rating is given but may be adjusted downwards according to the nature of the sensitive data. 

Automated Detection

Related Guidelines

Bibliography