Weakness · High

CWE-836: Use of Password Hash Instead of Password for Authentication

What it is

The product records password hashes in a data store, receives a hash of a password from a client, and compares the supplied hash to the hash obtained from the data store.

MITRE CWE 4.19.1

Severity (our rating)
High
Likelihood of exploit
Not rated by MITRE
Introduced during
Implementation
Exploited in the wild
No CVE in CISA's catalog

In more detail

Some authentication mechanisms rely on the client to generate the hash for a password, possibly to reduce load on the server or avoid sending the password across the network. However, when the client is used to generate the hash, an attacker can bypass the authentication by obtaining a copy of the hash, e.g. by using SQL injection to compromise a database of authentication credentials, or by exploiting an information exposure. The attacker could then use a modified client to replay the stolen hash without having knowledge of the original password. As a result, the server-side comparison against a client-side hash does not provide any more security than the use of passwords without hashing.

What an attacker can do

  • Bypass Protection Mechanism (Access Control)
  • Gain Privileges or Assume Identity (Access Control)

How to prevent it

MITRE lists no specific mitigation for this weakness. Treat it like its parent weaknesses below: validate input, keep the design simple and review the code where it could appear.

CWE-836 on MITRE's CWE site

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Source: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.