CVE-2023-4110 in Availability Booking Calendar
Summary
by MITRE • 08/03/2023
A vulnerability has been found in PHP Jabbers Availability Booking Calendar 5.0 and classified as problematic. Affected by this vulnerability is an unknown functionality of the file /index.php. The manipulation of the argument session_id leads to cross site scripting. The attack can be launched remotely. The identifier VDB-235957 was assigned to this vulnerability. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 08/24/2023
The vulnerability identified as CVE-2023-4110 represents a critical cross-site scripting flaw within PHP Jabbers Availability Booking Calendar version 5.0, demonstrating a significant security weakness that impacts the core booking functionality of this web application. This vulnerability specifically affects the session_id parameter handling within the application's index.php file, creating an attack vector that allows malicious actors to inject arbitrary JavaScript code into the victim's browser. The flaw stems from inadequate input validation and sanitization of the session_id parameter, which is processed without proper security controls to prevent malicious code execution. The vulnerability's classification as remotely exploitable indicates that attackers can leverage this weakness through network-based attacks without requiring physical access to the target system.
The technical implementation of this XSS vulnerability occurs when the application fails to properly sanitize user-supplied session_id values before incorporating them into the application's response. This improper handling allows an attacker to craft a malicious session_id parameter containing JavaScript code that gets executed in the context of a victim's browser session. The vulnerability's impact extends beyond simple script execution as it can enable session hijacking, data theft, and further exploitation of the compromised user's privileges within the booking calendar application. The flaw operates under CWE-79 which specifically addresses cross-site scripting vulnerabilities, making it a direct descendant of well-known web application security weaknesses. Attackers can leverage this vulnerability to execute malicious scripts in the victim's browser, potentially stealing session cookies, modifying application data, or redirecting users to malicious websites.
The operational impact of CVE-2023-4110 poses substantial risks to organizations relying on PHP Jabbers Availability Booking Calendar for their scheduling and booking operations. A successful exploitation could allow attackers to impersonate legitimate users, access sensitive booking data, modify calendar entries, or even gain unauthorized access to the underlying system resources. The vulnerability's remote exploitability means that attackers can target users from anywhere on the internet without requiring any special privileges or local access. This creates a particularly dangerous scenario where unauthorized parties can manipulate booking systems, potentially causing significant business disruption, financial loss, or privacy breaches. The lack of vendor response to early disclosure attempts compounds the risk, as organizations may be left without official patches or mitigation guidance during the vulnerable period.
Security practitioners should implement immediate mitigations including input validation and output encoding for all user-supplied parameters, particularly those related to session management. The recommended approach involves implementing strict sanitization of the session_id parameter before processing, utilizing proper HTML entity encoding for all dynamic content, and implementing Content Security Policy headers to limit script execution. Organizations should also consider implementing web application firewalls to detect and block malicious session_id parameter values, while establishing monitoring procedures to identify potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1566 which covers social engineering tactics, as attackers may use this vulnerability to deliver malicious payloads through phishing campaigns or compromised booking interfaces. Additionally, organizations should conduct thorough security assessments of their booking calendar systems and ensure all web applications follow secure coding practices to prevent similar vulnerabilities from emerging in the future.