CVE-2016-2784 in CMS Made Simple
Summary
by MITRE
CMS Made Simple 2.x before 2.1.3 and 1.x before 1.12.2, when Smarty Cache is activated, allow remote attackers to conduct cache poisoning attacks, modify links, and conduct cross-site scripting (XSS) attacks via a crafted HTTP Host header in a request.
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Analysis
by VulDB Data Team • 01/30/2025
The vulnerability identified as CVE-2016-2784 affects CMS Made Simple content management systems version 2.x prior to 2.1.3 and version 1.x prior to 1.12.2. This security flaw specifically manifests when the Smarty caching mechanism is enabled within the application. The core issue stems from improper handling of HTTP Host headers during cache operations, creating a significant security risk that can be exploited by remote attackers without authentication. The vulnerability resides in the application's failure to properly validate and sanitize input from HTTP headers before incorporating them into cached content structures.
The technical exploitation of this vulnerability occurs through manipulation of the HTTP Host header field in crafted requests. When Smarty caching is active, the application processes this header field and incorporates it into cached responses without adequate sanitization measures. This allows attackers to inject malicious content that gets cached and subsequently served to other users. The flaw creates a cache poisoning scenario where legitimate cache entries become corrupted with malicious data, enabling attackers to modify links and inject cross-site scripting payloads. The vulnerability specifically impacts the cache generation and retrieval mechanisms, where the Host header value is directly used in constructing cached content without proper validation or encoding.
The operational impact of CVE-2016-2784 extends beyond simple cache corruption to enable persistent cross-site scripting attacks that can compromise user sessions and data integrity. When attackers successfully poison the cache with malicious Host header values, they can inject JavaScript code that executes in the context of other users' browsers. This creates a vector for session hijacking, data exfiltration, and further attack escalation. The vulnerability affects the application's trust model since cached content becomes tainted, potentially affecting multiple users who access the poisoned cache entries. The impact is particularly severe in environments where CMS Made Simple serves high-traffic websites with active caching, as the malicious content can reach numerous users simultaneously.
This vulnerability maps to CWE-93, which describes improper neutralization of CRLF characters in HTTP headers, and aligns with ATT&CK technique T1566 for credential access through cache poisoning. The attack surface is broad since it leverages fundamental HTTP header processing mechanisms that are commonly used across web applications. Organizations should implement immediate mitigations including disabling Smarty caching when not required, implementing proper input validation for HTTP headers, and applying the vendor-provided patches for versions 2.1.3 and 1.12.2. Additional protective measures include monitoring for unusual Host header values in web logs and implementing web application firewalls that can detect and block suspicious header manipulations. The vulnerability highlights the critical importance of validating all user-supplied input, including HTTP headers, in web applications to prevent cache-based attack vectors that can persist across multiple user sessions and compromise long-term system integrity.