CVE-2017-11737 in Rspamd
Summary
by MITRE
interface/js/app/history.js in WebUI in Rspamd before 1.6.3 allows XSS via the Subject and Message-Id headers, which are mishandled in the history page.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-11737 resides within the WebUI component of Rspamd version 1.6.2 and earlier, specifically affecting the interface/js/app/history.js file. This flaw represents a cross-site scripting vulnerability that exploits improper handling of user-supplied data within the history page functionality. The vulnerability manifests when the application processes Subject and Message-Id headers from email messages, failing to adequately sanitize or escape these inputs before rendering them in the web interface. The affected Rspamd WebUI component serves as the primary administrative interface for managing spam filtering operations, making this vulnerability particularly concerning for email security administrators who rely on the system for monitoring and managing email traffic. The history page functionality is designed to display message metadata including subject lines and message identifiers, but the application fails to implement proper input validation and output encoding mechanisms for these specific header fields.
The technical exploitation of this vulnerability occurs through the manipulation of email headers that are processed by the WebUI's history module. When malicious actors craft email messages containing specially formatted Subject or Message-Id headers, these inputs are directly rendered in the browser without proper sanitization. The vulnerability aligns with CWE-79, which categorizes cross-site scripting flaws as weaknesses in input validation and output encoding. Attackers can leverage this vulnerability to inject malicious scripts that execute within the context of the victim's browser session, potentially leading to session hijacking, credential theft, or unauthorized actions within the Rspamd administrative interface. The flaw demonstrates a classic improper neutralization of input during web output, where user-controllable data flows directly into HTML content without appropriate escaping or encoding.
The operational impact of CVE-2017-11737 extends beyond simple script execution, as it provides attackers with potential access to sensitive administrative functions within the Rspamd system. An attacker who successfully exploits this vulnerability could gain unauthorized access to email message histories, potentially exposing sensitive information contained within email headers, or could manipulate the display of message data to mislead administrators. This vulnerability also aligns with ATT&CK technique T1059.007, which covers scripting through web shells, and could facilitate further attacks by enabling persistent access to the administrative interface. The vulnerability affects organizations that rely on Rspamd for email filtering and security management, particularly those with web-based administrative access, as it undermines the integrity of the WebUI and potentially compromises the security of email infrastructure.
Mitigation strategies for CVE-2017-11737 focus on implementing proper input validation and output encoding mechanisms within the WebUI components. Organizations should immediately upgrade to Rspamd version 1.6.3 or later, where the vulnerability has been addressed through proper sanitization of Subject and Message-Id header inputs. System administrators should implement additional defensive measures including input validation at multiple layers, output encoding for all user-supplied data, and regular security assessments of web applications. The fix typically involves implementing proper HTML escaping or encoding for all dynamic content rendered in the history page, ensuring that special characters in user inputs are properly handled. Security monitoring should include detection of unusual patterns in email headers that might indicate exploitation attempts, and network-based intrusion detection systems should be configured to identify potential XSS payloads in email traffic. Organizations should also consider implementing web application firewalls and content security policies to provide additional layers of protection against similar vulnerabilities.