CVE-2020-8789 in Composr
Summary
by MITRE
Composr 10.0.30 allows Persistent XSS via a Usergroup name under the Security configuration.
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Analysis
by VulDB Data Team • 05/22/2020
The vulnerability identified as CVE-2020-8789 affects Composr version 10.0.30 and represents a persistent cross-site scripting flaw that occurs when usergroup names are manipulated within the security configuration settings. This issue enables attackers to inject malicious scripts that persist across user sessions and can be executed whenever the affected page is loaded, making it particularly dangerous for web applications that handle sensitive security configurations.
The technical root cause of this vulnerability stems from inadequate input validation and output encoding within the Composr content management system's usergroup management functionality. When administrators or users create or modify usergroup names through the security configuration interface, the application fails to properly sanitize the input data before storing it in the database. This omission allows malicious payloads to be stored as legitimate usergroup names, which are then rendered without proper HTML escaping when displayed in subsequent administrative interfaces or user-facing pages. The vulnerability specifically manifests when the application retrieves these stored usergroup names and displays them in contexts where HTML content should be treated as plain text rather than executable code.
The operational impact of this persistent XSS vulnerability extends beyond simple data theft or session hijacking. Attackers can leverage this flaw to execute arbitrary JavaScript code within the context of authenticated user sessions, potentially gaining full administrative privileges or accessing sensitive configuration data. The persistence aspect means that once the malicious payload is injected, it will continue to affect all users who encounter the affected usergroup names, making it particularly difficult to contain and remediate. This vulnerability affects the integrity of the entire security configuration system, as usergroup names are fundamental components used for access control and permission management within the application.
From a cybersecurity perspective, this vulnerability aligns with CWE-79 Cross-site Scripting and falls under the ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, representing a significant threat to web application security. The persistent nature of this XSS vulnerability makes it particularly concerning as it can be exploited to establish long-term access to systems, potentially allowing attackers to modify security settings, create backdoor accounts, or exfiltrate sensitive data. Organizations using Composr 10.0.30 are advised to implement immediate mitigations including input sanitization, output encoding, and regular security audits of configuration interfaces to prevent exploitation of this vulnerability.
The remediation approach should prioritize updating to a patched version of Composr where the input validation has been strengthened and proper output encoding has been implemented for all user-controllable fields within the security configuration. Additionally, administrators should implement web application firewalls that can detect and block known XSS patterns, conduct regular security assessments of all user-facing configuration interfaces, and establish proper input validation procedures that sanitize all user-supplied data before storage. The vulnerability serves as a reminder of the critical importance of proper input validation and output encoding in web applications, particularly those handling security-sensitive configuration data. Organizations should also consider implementing automated monitoring systems that can detect anomalous usergroup name patterns that might indicate attempted exploitation of similar vulnerabilities.