Описание
Beego allows Reflected/Stored XSS in Beego's RenderForm() Function Due to Unescaped User Input
Summary
A Cross-Site Scripting (XSS) vulnerability exists in Beego's RenderForm() function due to improper HTML escaping of user-controlled data. This vulnerability allows attackers to inject malicious JavaScript code that executes in victims' browsers, potentially leading to session hijacking, credential theft, or account takeover. The vulnerability affects any application using Beego's RenderForm() function with user-provided data. Since it is a high-level function generating an entire form markup, many developers would assume it automatically escapes attributes (the way most frameworks do).
Details
The vulnerability is located in the renderFormField() function in Beego's templatefunc.go file (around lines 316-356). This function directly injects user-provided values into HTML without proper escaping:
None of the values (label, id, class, name, value) are properly HTML-escaped before being inserted into the HTML template. This allows attackers to break out of the attribute context or inject HTML tags directly. The vulnerability can be exploited in two main ways:
- Attribute Injection: By injecting code into fields like DisplayName, an attacker can break out of the attribute context and execute JavaScript.
- Content Injection: By injecting HTML tags into textarea content, an attacker can execute JavaScript.
The RenderForm() function returns template.HTML, which bypasses Go's automatic HTML escaping, making this vulnerability particularly dangerous.
PoC
Retrieve the following (secret) gist: https://gist.github.com/thevilledev/8fd0cab3f098320aa9daab04be59fd2b
To run it:
Open your browser and navigate to http://localhost:8080/
The application demonstrates the vulnerability through several examples:
/profile- Shows a profile with malicious data in the Display Name and Bio fields/admin- Shows multiple user profiles, including one with malicious data/submit- Allows you to create your own profile with malicious data
In addition, you may use this Go test in templatefunc_test.go. The test passes, validating the vulnerability.
Impact
This is a high-severity vulnerability with the following impacts:
- Cross-Site Scripting (XSS): Allows execution of arbitrary JavaScript in the context of the victim's browser.
- Session Hijacking: Attackers can steal session cookies and impersonate victims.
- Credential Theft: Attackers can create fake login forms to steal credentials.
- Account Takeover: Attackers can perform actions on behalf of the victim.
- Data Exfiltration: Sensitive data visible in the browser can be stolen.
This is particularly concerning in admin panels or user management interfaces where one user's data is displayed to another user (typically an administrator).
Mitigation
The vulnerability can be fixed by properly escaping all user-provided values before inserting them into HTML, for example:
Пакеты
github.com/beego/beego/v2
< 2.3.6
2.3.6
github.com/beego/beego
<= 1.12.14
Отсутствует
Связанные уязвимости
Beego is an open-source web framework for the Go programming language. Prior to 2.3.6, a Cross-Site Scripting (XSS) vulnerability exists in Beego's RenderForm() function due to improper HTML escaping of user-controlled data. This vulnerability allows attackers to inject malicious JavaScript code that executes in victims' browsers, potentially leading to session hijacking, credential theft, or account takeover. The vulnerability affects any application using Beego's RenderForm() function with user-provided data. Since it is a high-level function generating an entire form markup, many developers would assume it automatically escapes attributes (the way most frameworks do). This vulnerability is fixed in 2.3.6.