CVE-2017-16906 in Horde Groupware
Summary
by MITRE
In Horde Groupware 5.2.19, there is XSS via the URL field in a "Calendar -> New Event" action.
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Analysis
by VulDB Data Team • 01/11/2023
The vulnerability identified as CVE-2017-16906 represents a cross-site scripting weakness within Horde Groupware version 5.2.19 that specifically manifests when users interact with the calendar module's event creation functionality. This issue arises from insufficient input validation and output encoding mechanisms in the web application's handling of URL parameters within the calendar event creation workflow. The flaw exists in the application's user interface where the URL field in the "Calendar -> New Event" action fails to properly sanitize user-supplied input before rendering it in the web page context, creating an avenue for malicious actors to inject arbitrary script code that executes in the context of other users' browsers.
The technical nature of this vulnerability aligns with CWE-79 which describes improper neutralization of input during web page generation, specifically categorizing it as a cross-site scripting flaw. This weakness allows attackers to craft malicious URLs containing script payloads that, when processed by the vulnerable application, get executed in the browsers of unsuspecting users who view the affected calendar events. The attack vector is particularly concerning because it requires minimal user interaction beyond navigating to a specially crafted URL that triggers the calendar event creation interface, making it susceptible to phishing campaigns or malicious link distribution.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, data exfiltration, and privilege escalation within the application's context. When exploited, the XSS vulnerability could allow an attacker to steal authentication cookies or session tokens from authenticated users, potentially leading to full account compromise and unauthorized access to calendar data, contacts, and other sensitive information stored within the Horde Groupware environment. The vulnerability affects all users who have access to the calendar module and can be exploited through various attack vectors including social engineering, compromised websites, or direct link sharing.
Organizations utilizing Horde Groupware 5.2.19 should implement immediate mitigations including input validation and output encoding controls that sanitize all user-supplied data before rendering it in web contexts. The recommended approach involves implementing proper HTML escaping mechanisms for all dynamic content, particularly URL parameters and form inputs within the calendar event creation workflow. Additionally, implementing content security policies and using secure coding practices that follow the OWASP Secure Coding Practices can significantly reduce the risk of exploitation. The vulnerability also highlights the importance of regular security updates and patch management, as this issue was resolved in subsequent versions of the application through proper input validation and sanitization measures. Security teams should also consider implementing web application firewalls to detect and block malicious payloads attempting to exploit this vulnerability while monitoring for suspicious user behavior patterns that might indicate exploitation attempts.