how to identify and exploit information disclosure vulnerabilities
In this section, we’ll cover the fundamentals of information disclosure vulnerabilities, explain how to identify and exploit them, and provide tips for preventing these vulnerabilities on your own websites.
Mastering the identification and exploitation of information disclosure is an essential skill for testers. You’ll likely encounter these vulnerabilities frequently, and understanding how to effectively exploit them can boost your testing efficiency and help you discover more critical bugs.
- Labs
If you're already familiar with the basics of information disclosure vulnerabilities and want to practice exploiting them on realistic, deliberately vulnerable targets, you can access all the relevant labs using the link below.
View all information disclosure labs
What is Information Disclosure?
Information disclosure, also called information leakage, occurs when a website unintentionally reveals sensitive data to users. Depending on the context, a website may expose various types of information to an attacker, such as:
- User data like usernames or financial details
- Sensitive business or commercial data
- Technical information about the website and its infrastructure
The risks of leaking user or business data are apparent, but disclosing technical details can also pose serious threats. While some of this information may seem minor, it can serve as a gateway to exposing further vulnerabilities. The insights gained could even be the missing link for constructing complex, high-severity attacks.
Sensitive information might sometimes be leaked to users simply browsing the website normally. More often, though, an attacker must engage with the site in unusual or malicious ways to trigger this disclosure. The attacker will then analyze the website’s responses to uncover potentially valuable data.
Examples of Information Disclosure
Some common examples of information disclosure include:
- Revealing hidden directories, their structure, or contents via a robots.txt file or directory listing
- Providing access to source code files through temporary backups
- Including database table or column names in error messages
- Exposing sensitive data, such as credit card details, unnecessarily
- Hard-coding API keys, IP addresses, or database credentials in the source code
- Hinting at the presence or absence of resources, usernames, etc., through subtle differences in application behavior
In this topic, you’ll learn how to find and exploit these examples and more.
How Do Information Disclosure Vulnerabilities Arise?
Information disclosure vulnerabilities can occur in various ways, but they generally fall into these categories:
- Failure to remove internal content from public-facing content: For instance, developer comments in the markup might be visible to users in the live environment.
- Insecure configuration of the website and associated technologies: Leaving debugging or diagnostic features enabled, for example, can provide attackers with useful tools to obtain sensitive data. Default configurations, such as overly verbose error messages, can also expose websites to risk.
- Flawed application design and behavior: A website might return distinct responses for different error states, enabling attackers to extract sensitive information, such as valid user credentials.
What is the Impact of Information Disclosure Vulnerabilities?
The impact of information disclosure depends on the website’s purpose and the information obtained by the attacker. In some cases, the exposure of sensitive data alone can have severe consequences. For example, an online store leaking customers’ credit card details would face significant repercussions.
Conversely, leaking technical data, such as directory structures or third-party framework usage, may have little immediate impact. However, in the wrong hands, this information could enable the creation of further exploits. The severity, in this case, depends on how the attacker uses the information.
How to Assess the Severity of Information Disclosure Vulnerabilities
While information disclosure can have severe consequences, it’s usually only considered a high-severity issue in specific cases. The disclosure of technical information, for example, is often relevant only if you can demonstrate how an attacker could exploit it.
For instance, knowing that a website uses a specific framework version is insignificant if the version is fully patched. But if the site uses an outdated version with known vulnerabilities, it opens the door to significant attacks using publicly available exploits.
It’s important to use common sense when identifying leaked sensitive data. Many websites unintentionally reveal minor technical details. Your primary focus should be on the potential impact and exploitability of the leaked data rather than treating information disclosure as a standalone issue. The exception is when the leaked information is so sensitive that it warrants immediate attention.
Exploiting Information Disclosure
We’ve compiled practical guidance to help you identify and exploit these vulnerabilities. You can also practice these skills using our interactive labs.
How to Prevent Information Disclosure Vulnerabilities
Completely preventing information disclosure is challenging due to the various ways it can occur. However, following these best practices can significantly reduce the risk:
- Ensure everyone involved in the website’s production understands what information is sensitive. Sometimes seemingly harmless data can be much more valuable to an attacker than it appears. Raising awareness of these dangers helps ensure that sensitive information is securely handled.
- Conduct audits of code for potential information disclosure as part of your QA or build processes. Some tasks, like stripping developer comments, can be automated.
- Use generic error messages whenever possible to avoid giving attackers unnecessary clues about application behavior.
- Double-check that debugging or diagnostic features are disabled in the production environment.
- Fully understand the configuration and security implications of any third-party technologies you use. Disable any unneeded features and settings.
