Weakness · High
CWE-804: Guessable CAPTCHA
What it is
The product uses a CAPTCHA challenge, but the challenge can be guessed or automatically recognized by a non-human actor.
- Severity (our rating)
- High
- Likelihood of exploit
- Not rated by MITRE
- Introduced during
- Architecture and Design, Implementation
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
An automated attacker could bypass the intended protection of the CAPTCHA challenge and perform actions at a higher frequency than humanly possible, such as launching spam attacks. There can be several different causes of a guessable CAPTCHA: An audio or visual image that does not have sufficient distortion from the unobfuscated source image. A question is generated with a format that can be automatically recognized, such as a math question. A question for which the number of possible answers is limited, such as birth years or favorite sports teams. A general-knowledge or trivia question for which the answer can be accessed using a data base, such as country capitals or popular entertainers. Other data associated with the CAPTCHA may provide hints about its contents, such as an image whose filename contains the word that is used in the CAPTCHA.
What an attacker can do
- Bypass Protection Mechanism (Access Control, Other)
- Other (Access Control, Other)
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.
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Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.