CVE-2017-7725 in concrete5
Summary
by MITRE
concrete5 8.1.0 places incorrect trust in the HTTP Host header during caching, if the administrator did not define a "canonical" URL on installation of concrete5 using the "Advanced Options" settings. Remote attackers can make a GET request with any domain name in the Host header; this is stored and allows for arbitrary domains to be set for certain links displayed to subsequent visitors, potentially an XSS vector.
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Analysis
by VulDB Data Team • 08/24/2025
The vulnerability CVE-2017-7725 affects concrete5 version 8.1.0 and represents a critical security flaw in how the content management system handles HTTP Host header validation during caching operations. This issue stems from the application's improper trust in the HTTP Host header when no canonical URL has been explicitly defined during the installation process. The flaw exists within the core caching mechanism of concrete5, where the system relies on the Host header value to determine the domain context for cached content, creating a dangerous trust model that can be exploited by malicious actors.
The technical implementation of this vulnerability allows remote attackers to manipulate the HTTP Host header in GET requests to include arbitrary domain names. When concrete5 processes these requests and stores the Host header value in its caching system, it effectively becomes part of the application's internal domain resolution logic. This creates a scenario where subsequent visitors to the site may receive links and URLs that point to attacker-controlled domains, fundamentally compromising the integrity of the application's URL generation and caching mechanisms. The vulnerability operates at the HTTP protocol level and directly impacts the application's ability to maintain consistent domain context across cached content.
The operational impact of this vulnerability extends beyond simple domain manipulation and creates a significant vector for cross-site scripting attacks. When attackers can inject arbitrary domains into the cached links, they can potentially redirect users to malicious sites or craft phishing pages that appear legitimate within the context of the vulnerable concrete5 installation. This represents a severe degradation of the application's security posture as it allows attackers to manipulate the user experience and potentially harvest credentials or sensitive information. The vulnerability is particularly dangerous because it can be exploited without authentication and affects all users who access the vulnerable concrete5 installation.
Security mitigations for CVE-2017-7725 should focus on ensuring that administrators explicitly define canonical URLs during the installation process using the "Advanced Options" settings. The recommended approach involves implementing strict Host header validation mechanisms that verify the Host header against known legitimate domains before accepting it for caching purposes. Organizations should also consider implementing proper input sanitization and domain validation checks that prevent arbitrary domain injection into cached content. This vulnerability aligns with CWE-20, which covers "Improper Input Validation," and maps to ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" as the exploitation may involve JavaScript-based XSS payloads. Additionally, the issue relates to CWE-346, "Origin Validation Error," and can be classified under ATT&CK tactic TA0011 for "Command and Control" through the potential for redirecting users to malicious domains for data exfiltration purposes.