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CWE-309: Use of Password System for Primary Authentication

Weakness ID: 309
Abstraction: Base
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The use of password systems as the primary means of authentication may be subject to several flaws or shortcomings, each reducing the effectiveness of the mechanism.
+ Relationships

The table(s) below shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

+ Relevant to the view "Research Concepts" (CWE-1000)
+ Relevant to the view "Development Concepts" (CWE-699)
ChildOfClassClass287Improper Authentication
+ Background Details
Password systems are the simplest and most ubiquitous authentication mechanisms. However, they are subject to such well known attacks,and such frequent compromise that their use in the most simple implementation is not practical.
+ Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Architecture and Design
+ Applicable Platforms
The listings below show possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.


Class: Language-Independent (Undetermined Prevalence)

+ Common Consequences

The table below specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Access Control

Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity

A password authentication mechanism error will almost always result in attackers being authorized as valid users.
+ Likelihood Of Exploit
+ Demonstrative Examples

Example 1

In both of these examples, a user is logged in if their given password matches a stored password:

(bad code)
Example Language:
unsigned char *check_passwd(char *plaintext) {
ctext = simple_digest("sha1",plaintext,strlen(plaintext), ... );
//Login if hash matches stored hash

if (equal(ctext, secret_password())) {


(bad code)
Example Language: Java 
String plainText = new String(plainTextIn);
MessageDigest encer = MessageDigest.getInstance("SHA");
byte[] digest = password.digest();
//Login if hash matches stored hash

if (equal(digest,secret_password())) {


This code fails to incorporate more than one method of authentication. If an attacker can steal or guess a user's password, they are given full access to their account. Note this code also exhibits CWE-328 (Reversible One-Way Hash) and CWE-759 (Use of a One-Way Hash without a Salt).

+ Potential Mitigations

Phase: Architecture and Design

In order to protect password systems from compromise, the following should be noted:

  • Passwords should be stored safely to prevent insider attack and to ensure that -- if a system is compromised -- the passwords are not retrievable. Due to password reuse, this information may be useful in the compromise of other systems these users work with. In order to protect these passwords, they should be stored encrypted, in a non-reversible state, such that the original text password cannot be extracted from the stored value.
  • Password aging should be strictly enforced to ensure that passwords do not remain unchanged for long periods of time. The longer a password remains in use, the higher the probability that it has been compromised. For this reason, passwords should require refreshing periodically, and users should be informed of the risk of passwords which remain in use for too long.
  • Password strength should be enforced intelligently. Rather than restrict passwords to specific content, or specific length, users should be encouraged to use upper and lower case letters, numbers, and symbols in their passwords. The system should also ensure that no passwords are derived from dictionary words.

Phase: Architecture and Design

Use a zero-knowledge password protocol, such as SRP.

Phase: Architecture and Design

Ensure that passwords are stored safely and are not reversible.

Phase: Architecture and Design

Implement password aging functionality that requires passwords be changed after a certain point.

Phase: Architecture and Design

Use a mechanism for determining the strength of a password and notify the user of weak password use.

Phase: Architecture and Design

Inform the user of why password protections are in place, how they work to protect data integrity, and why it is important to heed their warnings.
+ Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CLASPUsing password systems
OWASP Top Ten 2004A3CWE More SpecificBroken Authentication and Session Management
+ Content History
Submission DateSubmitterOrganization
Modification DateModifierOrganization
Suggested OWASP Top Ten 2004 mapping
2008-09-08CWE Content TeamMITRE
updated Background_Details, Common_Consequences, Relationships, Taxonomy_Mappings
2010-12-13CWE Content TeamMITRE
updated Common_Consequences
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2012-10-30CWE Content TeamMITRE
updated Demonstrative_Examples
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, Likelihood_of_Exploit
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Using Password Systems

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Page Last Updated: January 18, 2018