CVE-2021-36092 in Community Edition
Summary
by MITRE • 07/26/2021
It's possible to create an email which contains specially crafted link and it can be used to perform XSS attack. This issue affects: OTRS AG ((OTRS)) Community Edition:6.0.x version 6.0.1 and later versions. OTRS AG OTRS: 7.0.x version 7.0.27 and prior versions; 8.0.x version 8.0.14 and prior versions.
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Analysis
by VulDB Data Team • 08/05/2021
The vulnerability identified as CVE-2021-36092 represents a cross-site scripting weakness within the OTRS (Open Technology Real-time Service) platform that enables attackers to execute malicious scripts through crafted email links. This flaw specifically impacts multiple versions of the OTRS Community Edition and OTRS software, creating a significant security risk for organizations relying on these platforms for customer service and ticket management operations. The vulnerability stems from insufficient input validation and output encoding mechanisms within the email processing functionality of the affected versions.
The technical implementation of this vulnerability occurs when the OTRS system processes incoming emails containing specially crafted hyperlinks that are not properly sanitized or encoded before being rendered in web interfaces. Attackers can construct malicious URLs that, when clicked by authenticated users, execute arbitrary JavaScript code within the victim's browser context. This occurs because the system fails to adequately filter or escape special characters and script tags that might be embedded within email addresses, URLs, or other link attributes. The vulnerability is classified under CWE-79 as a failure to sanitize or encode output, which directly enables cross-site scripting attacks. The flaw particularly affects the web-based user interface components where email content is displayed, allowing attackers to leverage the trust relationship between users and the legitimate OTRS application to execute malicious payloads.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to escalate privileges, steal session cookies, perform unauthorized actions within the application, and potentially access sensitive customer data or internal system information. Organizations using affected OTRS versions face risks of data breaches, unauthorized access to customer service tickets, and potential system compromise. The vulnerability is particularly dangerous in environments where OTRS serves as a central communication hub for customer support, as it can be exploited through legitimate email channels to target multiple users simultaneously. The attack vector requires minimal technical expertise to implement, making it attractive to threat actors who may leverage the vulnerability for phishing campaigns or credential theft operations. This weakness also aligns with ATT&CK technique T1566 which involves phishing and social engineering attacks that can be facilitated through crafted email content.
Mitigation strategies for CVE-2021-36092 should prioritize immediate patching of affected OTRS versions to the latest available releases that contain proper input validation and output encoding fixes. Organizations should implement additional security controls including web application firewalls that can detect and block suspicious URL patterns, enhanced email filtering systems that can identify potentially malicious links, and regular security assessments of email processing components. Network administrators should also consider implementing strict content security policies that prevent execution of inline scripts and restrict external resource loading. Security teams should conduct comprehensive vulnerability scans to identify any custom applications or integrations that might be vulnerable due to similar input handling issues. Regular security training for users on identifying suspicious email content and implementing multi-factor authentication can provide additional defense layers against exploitation attempts. The remediation process should include thorough testing of patched systems to ensure that legitimate functionality remains intact while the vulnerability is properly addressed.