CVE-2018-17883 in OTRS
Summary
by MITRE • 04/16/2023
An issue was discovered in Open Ticket Request System (OTRS) 6.0.x before 6.0.12. An attacker could send an e-mail message with a malicious link to an OTRS system or an agent. If a logged-in agent opens this link, it could cause the execution of JavaScript in the context of OTRS.
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Analysis
by VulDB Data Team • 05/05/2023
The vulnerability identified as CVE-2018-17883 affects the Open Ticket Request System OTRS version 6.0.x prior to 6.0.12, representing a critical cross-site scripting flaw that enables attackers to execute malicious JavaScript code within the context of the target system. This security weakness resides in the email processing functionality of OTRS, where the application fails to properly sanitize user-supplied input from incoming email messages before rendering them in the web interface. The vulnerability stems from insufficient validation and sanitization of email content, particularly hyperlinks and embedded elements that are automatically processed by the system when agents interact with email notifications.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious email containing a specially crafted link designed to execute JavaScript code within the OTRS web application context. When a logged-in agent opens such an email message, the malicious JavaScript code executes in the same security context as the legitimate user, potentially allowing for session hijacking, data exfiltration, or privilege escalation. This type of vulnerability is categorized under CWE-79 as Cross-Site Scripting, specifically reflecting the dangerous intersection of untrusted data processing and web application rendering. The flaw demonstrates poor input validation practices and inadequate output encoding mechanisms within the email handling subsystem of OTRS.
The operational impact of this vulnerability extends beyond simple script execution, as it creates a persistent attack vector that can compromise agent sessions and potentially escalate to full system compromise. An attacker who successfully exploits this vulnerability can manipulate the OTRS interface to perform actions on behalf of the compromised agent, including viewing sensitive customer data, modifying tickets, or accessing administrative functions depending on the agent's permissions. The attack requires minimal sophistication and can be executed through simple email delivery, making it particularly dangerous in enterprise environments where OTRS agents frequently handle sensitive customer information. This vulnerability aligns with ATT&CK technique T1566.001 for Phishing and T1059.007 for Command and Scripting Interpreter, as it enables both initial compromise through social engineering and subsequent execution of malicious code.
Organizations using affected OTRS versions should immediately implement the vendor-provided security patch available in version 6.0.12 or later, which addresses the input sanitization issues in the email processing module. Additional mitigations include implementing email filtering solutions that scan for suspicious link patterns, configuring strict content security policies within the OTRS web application, and educating agents about the dangers of opening untrusted email messages. Network-level protections such as web application firewalls can provide additional defense-in-depth, though the primary remediation must focus on the application-level patching and input validation improvements. The vulnerability highlights the importance of proper security practices in web applications, particularly regarding the handling of user-supplied content and the implementation of robust sanitization mechanisms to prevent XSS attacks.