CVE-2006-0182 in Calendar Project
Summary
by MITRE
login.php in ACal Calendar Project 2.2.5 allows remote attackers to bypass authentication by setting the ACalAuthenticate cookie variable to "inside".
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Analysis
by VulDB Data Team • 08/05/2017
The vulnerability described in CVE-2006-0182 affects the ACal Calendar Project version 2.2.5, specifically within the login.php script which handles user authentication processes. This represents a critical authentication bypass flaw that allows remote attackers to gain unauthorized access to calendar systems without proper credentials. The vulnerability stems from improper input validation and authentication logic implementation within the web application's session management mechanism.
The technical flaw manifests through the manipulation of a specific cookie variable named ACalAuthenticate. When an attacker sets this cookie value to "inside", the application incorrectly processes this input and grants access privileges as if the user had successfully authenticated. This occurs because the authentication routine fails to properly validate the cookie value against legitimate authentication states, creating a path for unauthorized access through predictable cookie manipulation. The vulnerability essentially creates a backdoor authentication mechanism that bypasses all normal authentication checks and validation procedures.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on the ACal Calendar system for scheduling and calendar management. Remote attackers can access calendar data, modify events, delete entries, and potentially gain access to sensitive information stored within the calendar system. The vulnerability affects the fundamental security model of the application, undermining the principle of least privilege and allowing unauthorized users to perform administrative functions. This authentication bypass can lead to data compromise, unauthorized modifications, and potential escalation to other system resources if the calendar application has access to broader network resources.
The vulnerability aligns with CWE-287 which addresses improper authentication issues in software systems. It also maps to several ATT&CK tactics including initial access through credential access and privilege escalation via authentication bypass techniques. Organizations using this vulnerable software face risks of persistent unauthorized access and potential data exfiltration. The attack vector is particularly concerning as it requires no local system access or complex exploitation techniques, making it accessible to any remote attacker who can manipulate cookies.
Mitigation strategies should include immediate patching of the ACal Calendar application to version 2.2.6 or later which addresses this authentication bypass vulnerability. Network administrators should implement cookie security measures including secure flags and HttpOnly attributes to prevent client-side cookie manipulation. Additionally, implementing proper input validation and authentication state management within the application code is essential. Organizations should also consider network segmentation and monitoring for unusual cookie patterns. Regular security assessments and vulnerability scanning should be conducted to identify similar authentication bypass issues in other applications. The incident highlights the critical importance of proper session management and authentication validation in web applications, particularly when dealing with sensitive calendar and scheduling data.