CVE-2018-17830 in Redaxo
Summary
by MITRE
The $args variable in addons/mediapool/pages/index.php in REDAXO 5.6.2 is not effectively filtered, because names are not restricted (only values are restricted). The attacker can insert XSS payloads via an index.php?page=mediapool/media&opener_input_field=&args[ substring.
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Analysis
by VulDB Data Team • 05/19/2023
The vulnerability identified as CVE-2018-17830 resides within the REDAXO content management system version 5.6.2, specifically in the mediapool addon's index.php file. This flaw represents a classic cross-site scripting vulnerability that stems from inadequate input validation practices within the application's parameter handling mechanisms. The vulnerability affects the $args variable processing logic where the system fails to properly sanitize or validate parameter names, creating an exploitable condition that allows malicious actors to inject arbitrary JavaScript code.
The technical implementation of this vulnerability occurs through the manipulation of URL parameters in the mediapool media page access point. Attackers can construct malicious URLs that exploit the lack of name restriction in the args array, specifically targeting the substring parameter within the args variable. The vulnerability's root cause lies in the asymmetric filtering approach where the system validates values but neglects to validate parameter names, creating a gap in the input sanitization process. This oversight allows attackers to inject malicious payloads that bypass the existing security controls designed to protect against XSS attacks.
The operational impact of this vulnerability is significant as it provides attackers with a direct pathway to execute arbitrary JavaScript code within the context of authenticated user sessions. This capability enables a range of malicious activities including session hijacking, data theft, privilege escalation, and the potential for establishing persistent backdoors within the CMS environment. The vulnerability affects users who have access to the mediapool functionality, making it particularly dangerous in environments where multiple users with varying privilege levels interact with the system. The attack vector requires minimal complexity to exploit and can be executed through simple URL manipulation techniques.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation that addresses both parameter names and values within the args array. The recommended approach involves applying strict sanitization rules to all parameter names, ensuring that only predefined safe characters and patterns are accepted. Security patches should enforce proper filtering mechanisms that validate parameter names against whitelisted patterns and reject any suspicious input. Organizations should also implement proper content security policies to limit the impact of potential XSS exploitation attempts. Additionally, the vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a technique that could be categorized under ATT&CK tactic TA0001 (Initial Access) and technique T1059.001 (Command and Scripting Interpreter) when exploited for malicious purposes. Regular security audits and input validation testing should be implemented to prevent similar vulnerabilities from emerging in other parts of the application codebase.