CVE-2016-6191 in SOGo
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the View Raw Source page in the Web Calendar in SOGo before 3.1.3 allow remote attackers to inject arbitrary web script or HTML via the (1) Description, (2) Location, (3) URL, or (4) Title field.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-6191 represents a critical cross-site scripting weakness in the SOGo web calendar application's View Raw Source page functionality. This flaw exists within the software's handling of user-supplied input across four distinct field types including Description, Location, URL, and Title parameters. The vulnerability affects versions of SOGo prior to 3.1.3, indicating a widespread issue that likely impacted numerous organizations relying on this calendar management system for collaborative work environments. The security implications are particularly severe given that SOGo serves as a comprehensive groupware solution providing email, calendar, and collaboration services for enterprise and organizational deployments.
The technical nature of this vulnerability stems from insufficient input validation and output encoding mechanisms within the web calendar's raw source viewing feature. When users navigate to the View Raw Source page, the application fails to properly sanitize or escape user-provided data before rendering it back to the browser. This creates an opportunity for malicious actors to inject arbitrary web scripts or HTML content through any of the four vulnerable fields. The flaw operates as a classic reflected XSS vulnerability where malicious payloads are executed in the context of the victim's browser session, potentially enabling attackers to steal session cookies, perform unauthorized actions, or redirect users to malicious sites. According to CWE classification, this represents a CWE-79: Cross-site Scripting vulnerability that specifically manifests in web applications through improper input validation and output encoding.
The operational impact of CVE-2016-6191 extends beyond simple data corruption or display issues, as it provides attackers with potential access to sensitive calendar information and user sessions. In enterprise environments where SOGo is deployed for collaborative work, this vulnerability could enable attackers to access confidential meeting details, personal contact information, and calendar entries that may contain sensitive business data. The remote exploitation capability means that attackers do not require physical access to the network or system, making the vulnerability particularly dangerous for organizations with distributed workforces or public-facing calendar services. Attackers could leverage this vulnerability to establish persistent access through session hijacking or to conduct more sophisticated social engineering campaigns by manipulating calendar entries to appear legitimate to end users.
Organizations affected by this vulnerability should prioritize immediate remediation through updating to SOGo version 3.1.3 or later, which contains the necessary patches to address the XSS flaws. System administrators should also implement additional security measures including web application firewalls, content security policies, and regular security assessments of calendar and collaboration applications. The vulnerability demonstrates the importance of input validation and output encoding practices as outlined in the OWASP Top Ten security framework, specifically addressing the need for proper sanitization of user inputs to prevent XSS attacks. Security teams should conduct comprehensive vulnerability assessments across all deployed web applications to identify similar input validation weaknesses that could be exploited through similar attack vectors. Additionally, implementing proper security monitoring and incident response procedures will help detect and respond to potential exploitation attempts that may occur before full patch deployment.