CVE-2019-18345 in DAViCal
Summary
by MITRE
A reflected XSS issue was discovered in DAViCal through 1.1.8. It echoes the action parameter without encoding. If a user visits an attacker-supplied link, the attacker can view all data the attacked user can view, as well as perform all actions in the name of the user. If the user is an administrator, the attacker can for example add a new admin user to gain full access to the application.
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Analysis
by VulDB Data Team • 03/11/2024
The vulnerability CVE-2019-18345 represents a critical reflected cross-site scripting flaw in the DAViCal calendar and scheduling application version 1.1.8 and earlier. This vulnerability resides in the application's handling of user input parameters, specifically the action parameter which is directly echoed back to users without proper output encoding or sanitization. The flaw allows attackers to inject malicious scripts into the application's response, which then executes in the context of the victim's browser session.
The technical nature of this vulnerability aligns with CWE-79 which describes improper neutralization of input during web page generation, making it a classic reflected XSS vulnerability. When a user clicks on a malicious link crafted by an attacker, the malicious script is executed within the user's browser session, leveraging the user's authenticated context. The application fails to implement proper input validation and output encoding mechanisms that would normally prevent such attacks from succeeding. The reflected nature of this vulnerability means that the malicious payload is embedded in the URL and reflected back by the server in the HTTP response, making it particularly effective for social engineering attacks.
The operational impact of this vulnerability is severe and multifaceted. Since the application handles calendar and scheduling data, attackers can access all information that the targeted user can view, including sensitive calendar entries, meeting details, and personal information. More critically, if the compromised user account has administrative privileges, the attacker can escalate their privileges and perform administrative actions such as creating new administrator accounts, modifying existing user permissions, or even deleting critical data. This creates a complete compromise of the application's security model and potentially exposes the entire organization's scheduling infrastructure to unauthorized access.
The security implications extend beyond simple data exposure to encompass full application compromise when administrative accounts are targeted. Attackers can leverage this vulnerability to establish persistent access through the creation of new administrative accounts, effectively bypassing all authentication mechanisms. This type of vulnerability is particularly dangerous in enterprise environments where DAViCal might be used for critical scheduling and collaboration functions. The attack vector requires user interaction through phishing or social engineering techniques, but once executed, it provides attackers with the same privileges as the compromised user, making it a significant threat to organizational security.
Mitigation strategies for this vulnerability include immediate application patching to version 1.1.9 or later which addresses the reflected XSS issue through proper input validation and output encoding. Organizations should implement comprehensive input sanitization measures that ensure all user-supplied parameters are properly encoded before being reflected back to users. Network administrators should also consider implementing web application firewalls that can detect and block malicious payloads targeting known XSS patterns. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications, while user education programs can help reduce the risk of successful social engineering attacks that exploit such vulnerabilities. The ATT&CK framework categorizes this as a web application attack vector under the T1059.008 technique for script injection, emphasizing the need for proper output encoding and input validation as primary defensive measures.