CVE-2017-6905 in concrete5
Summary
by MITRE
An issue was discovered in concrete5 <= 5.6.3.4. The vulnerability exists due to insufficient filtration of user-supplied data (disable_choose) passed to the "concrete5-legacy-master/web/concrete/tools/files/search_dialog.php" URL. An attacker could execute arbitrary HTML and script code in a browser in the context of the vulnerable website.
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Analysis
by VulDB Data Team • 12/29/2019
The vulnerability identified as CVE-2017-6905 affects concrete5 content management systems version 5.6.3.4 and earlier, representing a critical cross-site scripting flaw that stems from inadequate input validation mechanisms. This security weakness resides within the legacy file search dialog tool that processes user-supplied parameters without proper sanitization, creating an exploitable entry point for malicious actors seeking to inject malicious code into web applications. The specific parameter "disable_choose" within the search_dialog.php endpoint fails to implement adequate filtering measures, allowing attackers to manipulate the application's behavior through crafted input sequences.
The technical exploitation of this vulnerability occurs through the manipulation of the disable_choose parameter which is directly processed by the vulnerable script without appropriate HTML entity encoding or input sanitization. When users interact with the file search dialog functionality, the application fails to properly escape or validate the incoming data, enabling an attacker to inject malicious scripts that execute within the context of legitimate user sessions. This flaw specifically aligns with CWE-79, which categorizes cross-site scripting vulnerabilities as a result of insufficient input validation and output encoding. The vulnerability permits attackers to execute arbitrary HTML and script code in the browser context of authenticated users, potentially leading to session hijacking, credential theft, or further exploitation of the compromised application.
The operational impact of CVE-2017-6905 extends beyond simple script injection, as it provides attackers with the capability to manipulate user experiences and potentially escalate privileges within the concrete5 environment. Attackers can leverage this vulnerability to execute persistent XSS payloads that remain active until the user clears their browser cache or session data, creating long-term exposure risks for affected organizations. The vulnerability also aligns with ATT&CK technique T1059.002, which describes the use of scripting languages for executing malicious code, and T1566.001, which covers the exploitation of web applications through injection techniques. Organizations using concrete5 versions prior to 5.7.5.1 face significant risk of unauthorized access and data compromise, as the vulnerability allows for the execution of arbitrary code that could lead to complete application compromise.
Mitigation strategies for this vulnerability primarily focus on immediate application patching to version 5.7.5.1 or later, which includes proper input validation and output encoding mechanisms. System administrators should implement comprehensive input sanitization measures that validate all user-supplied data against whitelisted character sets and enforce proper HTML escaping for all dynamic content. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, though these should not replace proper code-level fixes. Organizations should also conduct thorough security assessments of their concrete5 installations to identify any other potentially vulnerable endpoints and ensure proper security configurations are in place. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and implementing robust input validation practices as outlined in OWASP Top Ten security guidelines, particularly focusing on prevention of injection attacks and proper output encoding mechanisms.