CWE-309: Use of Password System for Primary Authentication

Mitigation Strategies

Phase

Architecture and Design

Description

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

Description

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

Phase

Architecture and Design

Description

Ensure that passwords are stored safely and are not reversible.

Phase

Architecture and Design

Description

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

Phase

Architecture and Design

Description

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

Phase

Architecture and Design

Description

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.

Code Examples & CVEs

Demonstrative Examples

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

This code relies exclusively on a password mechanism (CWE-309) using only one factor of authentication (CWE-308). If an attacker can steal or guess a user's password, they are given full access to their account. Note this code also uses SHA-1, which is a weak hash (CWE-328). It also does not use a salt (CWE-759).

BadC

unsigned char *check_passwd(char *plaintext) {ctext = simple_digest("sha1",plaintext,strlen(plaintext), ... );                         //Login if hash matches stored hash                         if (equal(ctext, secret_password())) {login_user();}}

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

BadJava

String plainText = new String(plainTextIn);MessageDigest encer = MessageDigest.getInstance("SHA");encer.update(plainTextIn);byte[] digest = password.digest();                      //Login if hash matches stored hash                      if (equal(digest,secret_password())) {login_user();}

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-309 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-309, Use of Password System for Primary Authentication, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Use of Password System for Primary Authentication during Architecture and Design

MITRE associates mitigation with Architecture and Design; recorded impacts include Bypass Protection Mechanism, and Gain Privileges or Assume Identity; the entry maps to CAPEC-16, CAPEC-49, CAPEC-509, and CAPEC-55. Use these source-defined anchors to turn CWE-309 into implementation, review, and verification checks for the affected component.

CWE-309: Use of Password System for Primary Authentication — MITRE CWE

Triage CWE-309 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-309, Use of Password System for Primary Authentication, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-309

Apply MITRE's full root-cause mapping guidance when using CWE-309, Use of Password System for Primary Authentication. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-309 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-309, Use of Password System for Primary Authentication. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-309: Use of Password System for Primary Authentication?+

CWE-309: Use of Password System for Primary Authentication is a Common Weakness Enumeration (CWE) entry maintained by MITRE. 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.

What are the security consequences of Use of Password System for Primary Authentication?+

If exploited, CWE-309 (Use of Password System for Primary Authentication) it can compromise Access Control, leading to outcomes such as Bypass Protection Mechanism and Gain Privileges or Assume Identity.

How do you prevent or mitigate Use of Password System for Primary Authentication?+

Recommended mitigations for CWE-309 include: 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. Use a zero-knowledge password protocol, such as SRP. Ensure that passwords are stored safely and are not reversible.

Which programming languages are affected by Use of Password System for Primary Authentication?+

CWE-309 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-309 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

CWE-309: Use of Password System for Primary Authentication

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

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Description

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Detection Methods

Code Examples & CVEs

Demonstrative Examples

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-309 with SSDF evidence

Address Use of Password System for Primary Authentication during Architecture and Design

Triage CWE-309 against known exploitation evidence

Apply precise root-cause mapping to CWE-309

Validate CWE-309 with root-cause mapping checks

Frequently Asked Questions

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