CVE-2006-0657 in PHP Event Calendar
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Softcomplex PHP Event Calendar 1.5 allows remote authenticated users to inject arbitrary web script or HTML, and corrupt data, via the (1) username and (2) password parameters, which are not sanitized before being written to users.php. NOTE: while this issue was originally reported as XSS, the primary issue might be direct static code injection with resultant XSS.
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Analysis
by VulDB Data Team • 08/01/2017
The CVE-2006-0657 vulnerability affects the Softcomplex PHP Event Calendar version 1.5, representing a critical cross-site scripting weakness that enables authenticated attackers to execute malicious code within the application's context. This vulnerability specifically targets the username and password parameters within the users.php file, where input validation mechanisms fail to properly sanitize user-supplied data before processing. The flaw exists in the application's handling of user authentication parameters, creating a pathway for attackers to inject arbitrary web scripts or HTML code directly into the application's output streams.
The technical nature of this vulnerability aligns with CWE-79, which defines cross-site scripting as a code injection attack where malicious scripts are executed in the victim's browser. However, the classification as primarily a static code injection vulnerability with subsequent XSS consequences indicates a more severe threat vector than typical XSS vulnerabilities. The vulnerability operates by allowing authenticated users to manipulate the username and password fields in such a way that their input gets directly written to the users.php file without proper sanitization or encoding. This creates a direct injection point where malicious payloads can be stored and subsequently executed when the application processes these parameters.
From an operational perspective, the impact of this vulnerability extends beyond simple data corruption to encompass potential full system compromise. The authenticated nature of the attack means that an attacker must first obtain valid credentials, but once inside the system, they can manipulate the calendar application's user management functionality to inject malicious code. This code injection can result in session hijacking, data theft, privilege escalation, or even complete system takeover depending on the application's execution environment and permissions. The vulnerability's potential for data corruption means that legitimate user information could be altered or destroyed, while the XSS component could be used to redirect users to malicious sites or steal sensitive session cookies.
The attack vector demonstrates a fundamental flaw in input validation and output encoding practices within the PHP Event Calendar application. The vulnerability represents a failure in implementing proper security controls at multiple layers of the application architecture, particularly in the user management component where authentication parameters should undergo rigorous sanitization before being processed. Security practitioners should note that this vulnerability exploits the principle of least privilege by allowing authenticated users to perform actions that should be restricted to administrators or system-level operations. The weakness creates a persistent threat where malicious code can remain dormant until executed, potentially affecting all users who interact with the compromised calendar application.
Mitigation strategies should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application's codebase, particularly in the users.php file where the vulnerability manifests. The recommended approach includes implementing proper parameter sanitization routines that filter out or encode potentially dangerous characters before processing user input. Additionally, the application should enforce strict access controls and audit logging to detect unauthorized modifications to user data. Security measures should also include regular code reviews and penetration testing to identify similar vulnerabilities in other components of the application. The implementation of Content Security Policy headers and proper HTML encoding of output data can provide additional defense-in-depth measures against exploitation of this vulnerability. Organizations should also consider implementing Web Application Firewall rules to detect and block suspicious input patterns targeting this specific weakness, aligning with ATT&CK technique T1059.007 for command and scripting interpreter.