CVE-2017-0356 in Ikiwiki
Summary
by MITRE
A flaw, similar to to CVE-2016-9646, exists in ikiwiki before 3.20170111, in the passwordauth plugin s use of CGI::FormBuilder, allowing an attacker to bypass authentication via repeated parameters.
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2017-0356 represents a significant authentication bypass flaw within the ikiwiki content management system, specifically affecting versions prior to 3.20170111. This issue resides within the passwordauth plugin and demonstrates a critical weakness in how the system handles authentication parameters. The flaw operates by exploiting the interaction between ikiwiki and the CGI::FormBuilder module, creating a scenario where an attacker can manipulate parameter handling to circumvent the authentication process entirely. The vulnerability is particularly concerning as it allows unauthorized access to protected content and administrative functions without proper credentials, fundamentally undermining the security model of the application.
The technical implementation of this vulnerability stems from improper handling of repeated parameters in the authentication flow. When the passwordauth plugin processes authentication requests, it fails to properly validate or sanitize multiple parameters with identical names that may be submitted through the CGI interface. This behavior creates a condition where an attacker can craft malicious requests containing repeated parameters, effectively overriding legitimate authentication checks. The flaw directly relates to CWE-285, which addresses improper authorization within the Common Weakness Enumeration framework, and demonstrates how parameter handling can lead to privilege escalation. The vulnerability operates at the application layer and can be exploited through web-based attacks, making it particularly dangerous in environments where ikiwiki serves as a collaborative platform for content management.
The operational impact of CVE-2017-0356 extends beyond simple unauthorized access, as it can enable attackers to perform a wide range of malicious activities within the compromised system. Once authenticated, an attacker gains access to all content managed by ikiwiki, including sensitive documents, user data, and potentially the ability to modify or delete content. The vulnerability also opens pathways for further exploitation, as attackers can leverage the compromised system as a foothold for broader network penetration attempts. This aligns with ATT&CK technique T1078.004, which covers valid accounts obtained through exploitation, where the bypassed authentication provides attackers with legitimate access to system resources. The vulnerability affects organizations using ikiwiki for collaborative documentation, wikis, and content management systems, particularly those where sensitive information is stored and where access controls are critical.
Mitigation strategies for CVE-2017-0356 primarily focus on immediate version updates and parameter validation improvements. Organizations should upgrade to ikiwiki version 3.20170111 or later, which includes fixes for the parameter handling issue within the passwordauth plugin. Additionally, administrators should implement comprehensive input validation and sanitization measures to prevent repeated parameter exploitation, particularly in custom implementations or modified versions of the software. The fix addresses the root cause by ensuring proper parameter handling within the CGI::FormBuilder integration and implements stricter authentication validation. Security monitoring should include detection of unusual parameter patterns and repeated authentication attempts that may indicate exploitation attempts. Network segmentation and access controls should be implemented to limit the potential impact of successful exploitation, while regular security audits should verify proper parameter handling in all web applications. The vulnerability serves as a reminder of the importance of proper input validation and parameter handling in authentication systems, particularly in web applications where user-supplied data flows directly into security-critical functions.