CVE-2016-7137 in Plone
Summary
by MITRE
Multiple open redirect vulnerabilities in Plone CMS 5.x through 5.0.6, 4.x through 4.3.11, and 3.3.x through 3.3.6 allow remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via a URL in the referer parameter to (1) %2b%2bgroupdashboard%2b%2bplone.dashboard1%2bgroup/%2b/portlets.Actions or (2) folder/%2b%2bcontextportlets%2b%2bplone.footerportlets/%2b /portlets.Actions or the (3) came_from parameter to /login_form.
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Analysis
by VulDB Data Team • 09/26/2022
The CVE-2016-7137 vulnerability represents a critical open redirect flaw affecting multiple versions of the Plone Content Management System across its 3.x, 4.x, and 5.x release lines. This vulnerability specifically targets the referer parameter handling within the Plone authentication and navigation mechanisms, creating a pathway for malicious actors to manipulate user redirects. The flaw manifests in three distinct attack vectors that leverage different Plone URL patterns and parameter names to achieve the same malicious outcome of unauthorized redirection.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization of the referer header and specific parameter values within Plone's authentication flow. When users navigate to Plone's login form or dashboard interfaces, the system fails to properly validate the redirect destinations specified in the referer parameter or the dedicated came_from parameter. This allows attackers to craft malicious URLs that contain encoded redirect targets, such as the groupdashboard and contextportlets paths mentioned in the vulnerability description, enabling them to redirect users to arbitrary external domains.
From an operational security perspective, this vulnerability presents significant risks for organizations using Plone CMS, particularly those with high user interaction requirements. Attackers can exploit these open redirect vulnerabilities to conduct sophisticated phishing campaigns by redirecting users to malicious domains that appear legitimate within the Plone ecosystem. The impact extends beyond simple redirection since these attacks can be used to harvest credentials, distribute malware, or manipulate user behavior through deceptive interfaces that maintain the appearance of being part of the trusted Plone environment. The vulnerability affects not only the login process but also various dashboard and portlet management interfaces, amplifying the attack surface considerably.
The attack vectors described in the vulnerability affect multiple Plone components and interfaces, with the first two targeting group dashboard and context portlet management functionalities while the third targets the standard login form's redirect mechanism. This multi-pronged approach increases the probability of successful exploitation since attackers can choose the most appropriate vector based on the target environment and user behavior patterns. The encoded parameter names such as %2b%2bgroupdashboard%2b%2bplone.dashboard1%2bgroup/%2b/portlets.Actions demonstrate the sophisticated nature of the attack, requiring attackers to understand Plone's URL structure and parameter handling mechanisms.
Security practitioners should implement immediate mitigations including input validation of referer headers and explicit validation of redirect destinations against a known whitelist of trusted domains. Organizations should also consider implementing proper URL encoding validation and sanitization within Plone's authentication flows. The vulnerability aligns with CWE-601 Open Redirect vulnerability classification and can be mapped to ATT&CK technique T1566.001 Phishing, as it enables the creation of deceptive user experiences that can lead to credential theft or system compromise. Organizations should also consider implementing security headers such as Referrer-Policy to limit the information sent in referer headers and reduce the attack surface for such vulnerabilities. Regular security assessments and proper input validation practices should be enforced across all Plone installations to prevent similar vulnerabilities from emerging in future releases.