CVE-2015-1630 in Exchange Server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Outlook Web App (OWA) in Microsoft Exchange Server 2013 SP1 and Cumulative Update 7 allows remote attackers to inject arbitrary web script or HTML via a crafted URL, aka "Audit Report Cross Site Scripting Vulnerability."
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Analysis
by VulDB Data Team • 04/15/2022
The vulnerability identified as CVE-2015-1630 represents a critical cross-site scripting flaw discovered in Microsoft Exchange Server 2013 SP1 and Cumulative Update 7 within the Outlook Web App component. This security weakness specifically affects the audit report functionality of the web-based email client interface, creating a pathway for remote attackers to execute malicious code within the context of authenticated user sessions. The flaw stems from inadequate input validation and output encoding mechanisms within the OWA's report generation system, where user-supplied data is not properly sanitized before being rendered in web pages. Security researchers identified that when the system processes specially crafted URLs containing malicious script content, the application fails to adequately escape or filter the input, allowing attackers to inject arbitrary HTML and JavaScript code that executes in the victim's browser.
The technical exploitation of this vulnerability occurs through manipulation of URL parameters that are processed by the audit report feature of Exchange Server's web interface. Attackers can craft malicious URLs containing script tags or other HTML elements that get executed when users navigate to specific audit reports. The vulnerability falls under CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments or links. When successfully exploited, the malicious scripts can steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users without their knowledge. The impact extends beyond simple script execution as it can enable more sophisticated attacks including credential theft, data exfiltration, and privilege escalation within the email environment.
The operational implications of CVE-2015-1630 are severe for organizations relying on Microsoft Exchange Server for email services, as it provides attackers with a method to compromise user sessions and potentially gain access to sensitive email communications. The vulnerability particularly affects enterprise environments where Exchange Server serves as the primary email infrastructure, as authenticated users who visit malicious URLs can unknowingly execute attacker-controlled code. Organizations may experience unauthorized access to confidential emails, calendar entries, contact information, and other sensitive data stored within the Exchange environment. The attack surface is broad since audit reports are commonly accessed by administrators and users for monitoring purposes, making the vulnerability particularly dangerous in environments with high user activity. Additionally, the persistent nature of the flaw means that once exploited, attackers can maintain access through stolen session tokens and potentially escalate privileges within the Exchange infrastructure.
Mitigation strategies for CVE-2015-1630 should prioritize immediate application of Microsoft security patches and updates, specifically targeting Exchange Server 2013 SP1 and Cumulative Update 7. Organizations should implement comprehensive input validation measures and output encoding for all user-supplied data within web applications, particularly in report generation features. Network segmentation and web application firewalls can provide additional defense-in-depth layers to monitor and filter malicious traffic patterns. Security teams should conduct regular vulnerability assessments and penetration testing to identify similar input validation weaknesses in other web applications. Administrative users should be educated about the risks of clicking suspicious links and visiting untrusted websites, as social engineering remains a common attack vector for exploiting such vulnerabilities. The implementation of content security policies and strict access controls for audit report features can significantly reduce the potential impact of successful exploitation attempts. Regular monitoring of web application logs for suspicious URL patterns and unusual access behavior provides early detection capabilities for potential exploitation attempts. Organizations should also consider implementing multi-factor authentication and privileged access management solutions to limit the damage from successful attacks.