Storing passwords in a recoverable format

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Overview

The storage of passwords in a recoverable format makes them subject to password reuse attacks by malicious users. If a system administrator can recover the password directly - or use a brute force search on the information available to him -, he can use the password on other accounts.

Consequences

  • Confidentiality: User's passwords may be revealed.
  • Authentication: Revealed passwords may be reused elsewhere to impersonate the users in question.

Exposure period

  • Design: The method of password storage and use is often decided at design time.
  • Implementation: In some cases, the decision of algorithms for password encryption or hashing may be left to the implementers.

Platform

  • Languages: All
  • Operating platforms: All

Required resources

Access to read stored password hashes

Severity

Medium to High

Likelihood of exploit

Very High

Avoidance and mitigation

  • Design / Implementation: Ensure that strong, non-reversible encryption is used to protect stored passwords.

Discussion

The use of recoverable passwords significantly increases the chance that passwords will be used maliciously. In fact, it should be noted that recoverable encrypted passwords provide no significant benefit over plain-text passwords since they are subject not only to reuse by malicious attackers but also by malicious insiders.

Examples

In C\C++:

int VerifyAdmin(char *password) {

 if (strcmp(compress(password), compressed_password)) {
   printf("Incorrect Password!\n");
   return(0)
 }
 printf("Entering Diagnostic Mode�\n");
 return(1);

} In Java:

int VerifyAdmin(String password) {

 if (passwd.Eqauls(compress((compressed_password)) {
   return()0)
 }

//Diagnostic Mode

 return(1);

}

Related problems

  • Use of hard-coded passwords

Categories