CVE-2018-10125 in Contao
Summary
by MITRE
Contao before 4.5.7 has XSS in the system log.
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Analysis
by VulDB Data Team • 03/17/2020
The vulnerability identified as CVE-2018-10125 represents a cross-site scripting flaw within the Contao content management system affecting versions prior to 4.5.7. This issue resides in the system log functionality where user-supplied input is not properly sanitized before being rendered in the web interface. The flaw allows authenticated attackers with sufficient privileges to inject malicious scripts into the system log entries, which then execute in the context of other users who view these logs. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS attack vector where malicious code persists in the application's database and executes whenever the affected log entries are displayed.
The technical implementation of this vulnerability stems from insufficient input validation and output escaping mechanisms within Contao's logging subsystem. When administrators or other authenticated users perform actions that generate log entries, the system fails to properly encode or sanitize special characters in the logged data before presenting it in the web interface. This creates an environment where malicious actors can inject javascript payloads, html tags, or other malicious content into log entries through legitimate system interactions. The vulnerability is particularly concerning because system logs are typically viewed by administrators who may have elevated privileges, making the potential impact of successful exploitation significant.
The operational impact of CVE-2018-10125 extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, and privilege escalation. When administrators view compromised log entries, their browsers execute the injected scripts, potentially allowing attackers to steal administrative sessions, modify system configurations, or gain deeper access to the application environment. The attack requires authentication and appropriate privileges to insert malicious content into logs, but once established, the vulnerability can persist and affect multiple users who access the system logs. This makes the vulnerability particularly dangerous in environments where multiple administrators have access to system logs.
Mitigation strategies for this vulnerability include immediate upgrading to Contao version 4.5.7 or later, which contains the necessary patches to address the XSS flaw. Organizations should also implement proper input validation and output encoding mechanisms throughout their applications, ensuring that all user-supplied data is properly sanitized before being stored or displayed. Security teams should conduct regular vulnerability assessments of their content management systems and implement monitoring solutions to detect unauthorized log modifications. The ATT&CK framework categorizes this vulnerability under T1059.007 for Command and Scripting Interpreter: JavaScript, as the exploitation involves executing malicious javascript code through the web interface. Additionally, implementing principle of least privilege access controls for system log viewing and regular security training for administrators can help reduce the risk of exploitation. Organizations should also consider implementing web application firewalls and content security policies to provide additional layers of protection against such attacks.