CVE-2016-4877 in BaserCMS
Summary
by MITRE
Cross-site scripting vulnerability in baserCMS plugin Mail version 3.0.10 and earlier allows remote authenticated attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 09/25/2020
The CVE-2016-4877 vulnerability represents a critical cross-site scripting flaw discovered in the baserCMS Mail plugin version 3.0.10 and earlier. This vulnerability falls under the category of input validation and output encoding failures, specifically manifesting as a client-side attack vector that can be exploited by authenticated attackers with access to the system. The vulnerability stems from insufficient sanitization of user-supplied input within the plugin's processing mechanisms, creating an opportunity for malicious actors to inject malicious scripts into web pages viewed by other users.
The technical implementation of this vulnerability involves the failure to properly validate and escape user input before rendering it within web page contexts. Attackers with legitimate authentication credentials can leverage this weakness to inject malicious JavaScript code or HTML content through unspecified vectors within the Mail plugin functionality. This typically occurs when the application fails to implement proper input filtering or output encoding mechanisms, allowing crafted payloads to be executed in the context of other users' browsers. The vulnerability is particularly concerning because it requires only authenticated access, meaning that an attacker with valid user credentials can exploit this flaw without requiring additional privileges or complex attack vectors.
From an operational impact perspective, this vulnerability creates significant security risks for organizations using affected baserCMS installations. The ability to execute arbitrary scripts in users' browsers can lead to session hijacking, credential theft, data exfiltration, and redirection to malicious sites. Attackers could potentially escalate their privileges or gain access to sensitive information by exploiting this XSS vulnerability, especially if the affected users have administrative privileges within the baserCMS system. The attack surface is further expanded when considering that authenticated users may have access to sensitive data or system functions that could be leveraged for more extensive compromise.
The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in software applications. This weakness category encompasses various forms of XSS attacks including stored XSS, reflected XSS, and DOM-based XSS, with CVE-2016-4877 representing a stored XSS scenario where malicious input is permanently stored and later executed. From an attacker's perspective, this vulnerability maps to multiple ATT&CK techniques including T1059 for command and scripting interpreter and T1566 for phishing, as attackers can craft malicious payloads that exploit this weakness to deliver further attacks. The vulnerability also relates to T1190 for exploit public-facing application, as it represents a weakness in a publicly accessible web application component.
Organizations should implement immediate mitigation strategies including applying the vendor-provided patch or upgrade to version 3.0.11 or later of the Mail plugin to address this vulnerability. Additionally, implementing proper input validation and output encoding mechanisms within the application codebase can help prevent similar issues in the future. Security teams should conduct thorough code reviews focusing on input sanitization and output encoding practices, particularly within web applications that process user-supplied data. Network monitoring should be enhanced to detect potential exploitation attempts, and user access controls should be reviewed to minimize the impact of potential credential compromise. Regular vulnerability assessments and penetration testing should be conducted to identify and remediate similar weaknesses in other components of the baserCMS ecosystem.