CVE-2015-2241 in Django
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the contents function in admin/helpers.py in Django before 1.7.6 and 1.8 before 1.8b2 allows remote attackers to inject arbitrary web script or HTML via a model attribute in ModelAdmin.readonly_fields, as demonstrated by a @property.
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Analysis
by VulDB Data Team • 05/01/2022
The vulnerability described in CVE-2015-2241 represents a critical cross-site scripting flaw within the Django web framework's administrative interface. This vulnerability specifically affects Django versions prior to 1.7.6 and 1.8beta2, creating a significant security risk for applications that utilize Django's built-in admin interface. The flaw resides in the contents function located within admin/helpers.py, which handles the rendering of model attributes within the ModelAdmin readonly_fields configuration. Attackers can exploit this vulnerability by manipulating model attributes that are displayed in the admin interface, particularly those defined as @property decorators that are included in readonly_fields. The vulnerability demonstrates how insufficient input sanitization and output encoding can lead to arbitrary code execution within the context of a victim's browser session.
The technical implementation of this vulnerability stems from Django's failure to properly escape or sanitize user-supplied data when rendering model attributes within the administrative interface. When a @property is included in the readonly_fields configuration of a ModelAdmin class, the contents function processes this property without adequate HTML escaping or context-appropriate encoding. This creates a pathway for attackers to inject malicious JavaScript code or HTML content that gets executed in the browser context of authenticated administrators who view the affected pages. The vulnerability is particularly dangerous because it leverages the administrative interface where users typically have elevated privileges, making successful exploitation potentially catastrophic for system security. This flaw directly maps to CWE-79, which describes Cross-Site Scripting vulnerabilities where untrusted data is improperly incorporated into web pages without proper validation or escaping.
The operational impact of CVE-2015-2241 extends beyond simple data theft or defacement, as it can enable attackers to perform privilege escalation and maintain persistent access to affected systems. An attacker who successfully injects malicious script into the admin interface can potentially access sensitive data, modify database records, create new user accounts, or even execute commands on the underlying system if the admin interface has sufficient privileges. The vulnerability is especially concerning because Django's admin interface is commonly used by system administrators and developers who may inadvertently click on malicious links or have their sessions hijacked through this vector. The attack surface is broad since any Django application using the admin interface with user-controllable model attributes in readonly_fields is potentially vulnerable, making this a widespread concern across the Django ecosystem.
Mitigation strategies for this vulnerability require immediate patching of affected Django versions to 1.7.6 or later releases, or 1.8beta2 and beyond. Organizations should also implement proper input validation and output encoding practices when configuring readonly_fields in ModelAdmin classes, particularly when dealing with user-supplied data. The Django security team's response to this vulnerability highlights the importance of context-aware escaping mechanisms, where data rendered in different contexts requires different escaping approaches. Security practitioners should also consider implementing content security policies to limit the execution of inline scripts and monitor for suspicious activities in administrative interfaces. This vulnerability reinforces the ATT&CK framework's concept of privilege escalation through web application vulnerabilities, where initial access through XSS can lead to complete system compromise. Regular security audits of Django applications, including code reviews of admin interface configurations, should be conducted to identify similar patterns that could create additional attack vectors.