CVE-2017-7320 in Revolution
Summary
by MITRE
setup/controllers/language.php in MODX Revolution 2.5.4-pl and earlier does not properly constrain the language parameter, which allows remote attackers to conduct Cookie-Bombing attacks and cause a denial of service (cookie quota exhaustion), or conduct HTTP Response Splitting attacks with resultant XSS, via an invalid parameter value.
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Analysis
by VulDB Data Team • 08/24/2020
The vulnerability identified as CVE-2017-7320 resides within the MODX Revolution content management system version 2.5.4-pl and earlier, specifically in the setup/controllers/language.php file. This flaw represents a critical security oversight that stems from inadequate input validation and parameter sanitization within the application's language selection mechanism. The vulnerability manifests when the system fails to properly constrain the language parameter, creating an attack surface that can be exploited by remote adversaries to manipulate the application's behavior in dangerous ways.
The technical implementation of this vulnerability allows attackers to inject malicious values into the language parameter through HTTP requests, bypassing normal input validation procedures. When the application processes these malformed parameters, it fails to properly sanitize or validate the input before using it in cookie creation or HTTP response generation processes. This improper handling creates conditions where attackers can manipulate cookie storage mechanisms and potentially inject malicious content into HTTP responses. The vulnerability specifically enables two distinct attack vectors: cookie bombing attacks that consume excessive cookie storage quotas leading to denial of service conditions, and HTTP response splitting attacks that can result in cross-site scripting exploits.
From an operational impact perspective, this vulnerability poses significant risks to MODX installations and their users. The cookie bombing capability allows attackers to exhaust available cookie storage space, effectively preventing legitimate users from accessing the application or causing system instability through resource exhaustion. The HTTP response splitting component introduces additional security concerns by enabling XSS attacks that can compromise user sessions, steal sensitive information, or redirect users to malicious sites. The combined effect of these attack vectors can result in complete service disruption and potential data compromise within affected systems. This vulnerability directly maps to CWE-79 (Cross-site Scripting) and CWE-122 (Heap-based Buffer Overflow) categories, with implications for CWE-20 (Improper Input Validation) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer).
The attack surface for this vulnerability extends across multiple threat vectors within the MODX ecosystem, particularly affecting systems that rely on the setup process or language selection features. Attackers can exploit this weakness without requiring authentication, making it particularly dangerous for publicly accessible web applications. The vulnerability's impact is amplified when considering that MODX installations often handle sensitive content and user data, making the potential for data theft or service disruption more severe. Organizations using affected versions should consider implementing immediate mitigations, including input validation patches, web application firewalls, and comprehensive monitoring of cookie usage patterns. The ATT&CK framework categorizes this vulnerability under T1210 (Exploitation of Remote Services) and T1059 (Command and Scripting Interpreter) as attackers may leverage the XSS capabilities to establish persistent access or escalate privileges within compromised environments. This vulnerability demonstrates the critical importance of proper input validation and parameter handling in web applications, particularly in CMS platforms that manage user interactions and content delivery.