CWE-1007 Base Incompleto Medium likelihood

Insufficient Visual Distinction of Homoglyphs Presented to User

Definición

What is CWE-1007?

This vulnerability occurs when an application shows text or symbols to users without clearly distinguishing between characters that look identical or very similar (called homoglyphs). Because users can't easily tell these characters apart, they might misinterpret information and accidentally perform unsafe actions, like clicking a malicious link.

Homoglyphs are different characters that appear identical or nearly identical on screen. For example, a lowercase 'L' and an uppercase 'i' can look the same in many fonts, and the Latin 'A' is visually identical to the Greek 'Alpha'. While software treats these as completely different characters, users can't see the difference, creating a gap between what the system understands and what the user perceives. Attackers exploit this visual ambiguity to trick users. A common method is creating deceptive phishing links or hostnames that mimic trusted sites. Similarly, an attacker might register a username like 'Admin' (with a Cyrillic 'A') that looks identical to the real 'Admin' account, making malicious activity harder to spot in system logs. This highlights a critical need for interfaces to help users visually distinguish between potentially confusing characters.

Impacto en el mundo real

Real-world CVEs caused by CWE-1007

CVE-2013-7236

web forum allows impersonation of users with homoglyphs in account names
CVE-2012-0584

Improper character restriction in URLs in web browser
CVE-2009-0652

Incomplete denylist does not include homoglyphs of "/" and "?" characters in URLs
CVE-2017-5015

web browser does not convert hyphens to punycode, allowing IDN spoofing in URLs
CVE-2005-0233

homoglyph spoofing using punycode in URLs and certificates
CVE-2005-0234

homoglyph spoofing using punycode in URLs and certificates
CVE-2005-0235

homoglyph spoofing using punycode in URLs and certificates

Cómo lo explotan los atacantes

Ruta del atacante paso a paso

1
The following looks like a simple, trusted URL that a user may frequently access.
2
However, the URL above is comprised of Cyrillic characters that look identical to the expected ASCII characters. This results in most users not being able to distinguish between the two and assuming that the above URL is trusted and safe. The "e" is actually the "CYRILLIC SMALL LETTER IE" which is represented in HTML as the character &#x435, while the "a" is actually the "CYRILLIC SMALL LETTER A" which is represented in HTML as the character &#x430. The "p", "c", and "o" are also Cyrillic characters in this example. Viewing the source reveals a URL of "http://www.еxаmрlе.соm". An adversary can utilize this approach to perform an attack such as a phishing attack in order to drive traffic to a malicious website.
3
The following displays an example of how creating usernames containing homoglyphs can lead to log forgery.
4
Assume an adversary visits a legitimate, trusted domain and creates an account named "admin", except the 'a' and 'i' characters are Cyrillic characters instead of the expected ASCII. Any actions the adversary performs will be saved to the log file and look like they came from a legitimate administrator account.
5
Upon closer inspection, the account that generated three of these log entries is "аdmіn". Only the third log entry is by the legitimate admin account. This makes it more difficult to determine which actions were performed by the adversary and which actions were executed by the legitimate "admin" account.

Ejemplo de código vulnerable

Vulnerable code

The following looks like a simple, trusted URL that a user may frequently access.

Vulnerable

http://www.еxаmрlе.соm

Payload del atacante

The following looks like a simple, trusted URL that a user may frequently access.

Payload del atacante

http://www.еxаmрlе.соm

Ejemplo de código seguro

Secure pseudo

Seguro pseudo

// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}

What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.

Lista de prevención

How to prevent CWE-1007

Implementation Use a browser that displays Punycode for IDNs in the URL and status bars, or which color code various scripts in URLs. Due to the prominence of homoglyph attacks, several browsers now help safeguard against this attack via the use of Punycode. For example, Mozilla Firefox and Google Chrome will display IDNs as Punycode if top-level domains do not restrict which characters can be used in domain names or if labels mix scripts for different languages.
Implementation Use an email client that has strict filters and prevents messages that mix character sets to end up in a user's inbox. Certain email clients such as Google's GMail prevent the use of non-Latin characters in email addresses or in links contained within emails. This helps prevent homoglyph attacks by flagging these emails and redirecting them to a user's spam folder.

Señales de detección

How to detect CWE-1007

Manual Dynamic Analysis Moderate

If utilizing user accounts, attempt to submit a username that contains homoglyphs. Similarly, check to see if links containing homoglyphs can be sent via email, web browsers, or other mechanisms.

Auto-corrección de Plexicus

Plexicus detecta automáticamente CWE-1007 y abre un PR de corrección en menos de 60 segundos.

Codex Remedium escanea cada commit, identifica esta debilidad concreta y entrega un pull request listo para revisión con el parche. Sin tickets. Sin traspasos.

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Preguntas frecuentes

Frequently asked questions

¿Qué es CWE-1007?

¿Qué gravedad tiene CWE-1007?

MITRE califica la probabilidad de explotación como Media — la explotación es realista pero suele requerir condiciones específicas.

¿Qué lenguajes o plataformas se ven afectados por CWE-1007?

MITRE lists the following affected platforms: Web Based.

¿Cómo puedo prevenir CWE-1007?

Use a browser that displays Punycode for IDNs in the URL and status bars, or which color code various scripts in URLs. Due to the prominence of homoglyph attacks, several browsers now help safeguard against this attack via the use of Punycode. For example, Mozilla Firefox and Google Chrome will display IDNs as Punycode if top-level domains do not restrict which characters can be used in domain names or if labels mix scripts for different languages. Use an email client that has strict filters…

¿Cómo detecta y corrige Plexicus CWE-1007?

El motor SAST de Plexicus detecta la firma de flujo de datos para CWE-1007 en cada commit. Cuando hay coincidencia, nuestro agente Codex Remedium abre un PR de corrección con el código corregido, las pruebas y un resumen de una línea para el revisor.

¿Dónde puedo aprender más sobre CWE-1007?

MITRE publica la definición canónica en https://cwe.mitre.org/data/definitions/1007.html. También puedes consultar la documentación de OWASP y NIST para guías relacionadas.

Debilidades relacionadas

Weaknesses related to CWE-1007

CWE-451 Padre

User Interface (UI) Misrepresentation of Critical Information

This vulnerability occurs when a user interface fails to accurately display or highlight crucial information, potentially misleading users…

CWE-1021 Hermano

Improper Restriction of Rendered UI Layers or Frames

This vulnerability occurs when a web application fails to properly control whether its pages can be embedded within frames or UI layers…

Recursos

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