CVE-2011-1949 in Plone
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the safe_html filter in Products.PortalTransforms in Plone 2.1 through 4.1 allows remote authenticated users to inject arbitrary web script or HTML via unspecified vectors, a different vulnerability than CVE-2010-2422.
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Analysis
by VulDB Data Team • 02/09/2019
The CVE-2011-1949 vulnerability represents a cross-site scripting flaw within the safe_html filter component of Plone content management systems ranging from version 2.1 through 4.1. This vulnerability specifically affects the Products.PortalTransforms module which is responsible for sanitizing and filtering HTML content to prevent malicious scripts from being executed within the web application. The issue arises from insufficient input validation and sanitization mechanisms that fail to properly neutralize potentially dangerous HTML elements and script tags. Unlike CVE-2010-2422 which addressed a different class of XSS vulnerabilities, this particular flaw allows authenticated remote attackers to inject malicious web scripts or HTML code through unspecified attack vectors within the portal transformation process.
The technical implementation of this vulnerability stems from the safe_html filter's inadequate handling of user-supplied content that passes through the PortalTransforms system. When authenticated users submit content that contains malicious HTML or script elements, the filter fails to completely remove or encode these dangerous constructs before rendering them in web pages. This creates an environment where attackers can leverage their authenticated status to inject persistent or reflected XSS payloads that execute in the context of other users' browsers. The vulnerability's impact extends beyond simple script injection as it can enable session hijacking, credential theft, and other malicious activities that compromise the integrity of the Plone application and its user base.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Plone for content management, particularly those with multiple authenticated users. The authenticated nature of the attack means that malicious actors do not require external exploitation or social engineering to gain access to the XSS vector, as they can leverage their legitimate user privileges to inject malicious code. This makes the vulnerability particularly dangerous in environments where users have elevated permissions or where the application handles sensitive information. The attack surface includes any functionality that utilizes the safe_html filter for content processing, potentially affecting user profiles, content editing features, and any HTML-based input fields within the Plone interface.
Security practitioners should implement multiple layers of mitigation to address this vulnerability effectively. Immediate remediation involves upgrading to Plone versions that contain patches for CVE-2011-1949, as newer releases incorporate improved HTML sanitization mechanisms and enhanced input validation. Organizations should also consider implementing additional security controls such as Content Security Policy headers to limit script execution, input sanitization at multiple layers, and regular security audits of user-generated content. The vulnerability aligns with CWE-79 which categorizes cross-site scripting flaws, and corresponds to ATT&CK technique T1059.001 for command and scripting interpreter. Organizations must also ensure proper user access controls and monitoring to detect unauthorized content injection attempts that could exploit this vulnerability in the wild.