CVE-2015-2536 in Lync Server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Microsoft Lync Server 2013 and Skype for Business Server 2015 allows remote attackers to inject arbitrary web script or HTML via a crafted URL, aka "Skype for Business Server and Lync Server XSS Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 06/14/2022
The CVE-2015-2536 vulnerability represents a critical cross-site scripting flaw affecting Microsoft Lync Server 2013 and Skype for Business Server 2015 implementations. This vulnerability falls under the CWE-79 category, which specifically addresses cross-site scripting attacks where malicious code can be injected into web applications through user input. The flaw enables remote attackers to execute arbitrary web scripts or HTML content by crafting malicious URLs that exploit insufficient input validation mechanisms within the affected Microsoft communication platforms. The vulnerability is particularly concerning as it affects enterprise collaboration systems that handle sensitive business communications and user data, making it a prime target for attackers seeking to compromise corporate networks through social engineering or automated exploitation techniques.
The technical exploitation of this vulnerability occurs when the affected servers fail to properly sanitize user-supplied input parameters within URL structures. Attackers can craft specially formatted URLs containing malicious scripts that, when processed by the vulnerable server, get executed in the context of other users' browsers. This creates a persistent threat vector where legitimate users who click on the malicious links could have their sessions hijacked, sensitive information stolen, or their browsers redirected to malicious sites. The vulnerability is classified as an elevation of privilege issue because successful exploitation can potentially allow attackers to escalate their access rights within the communication environment, particularly when users with administrative privileges interact with the malicious content.
The operational impact of CVE-2015-2536 extends beyond simple script execution as it fundamentally compromises the security posture of organizations relying on these Microsoft communication platforms. Enterprise environments utilizing Lync Server 2013 or Skype for Business Server 2015 face significant risks including unauthorized access to sensitive business communications, potential data exfiltration through browser-based attacks, and the possibility of establishing persistent backdoors within the network. The vulnerability can be leveraged in conjunction with other attack vectors to create more sophisticated compromises, particularly when combined with phishing campaigns or credential harvesting techniques. Organizations may experience service disruption, compliance violations, and potential regulatory penalties if successful exploitation leads to data breaches or unauthorized access to corporate communications.
Microsoft addressed this vulnerability through security updates and patches released in their regular update cycle, but organizations needed to implement comprehensive remediation strategies including immediate patch deployment, network segmentation, and enhanced monitoring of user access patterns. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for 'Command and Scripting Interpreter: JavaScript' and T1566.001 for 'Phishing: Spearphishing Attachment', highlighting how attackers typically leverage such vulnerabilities for initial access and subsequent exploitation. Organizations should implement input validation controls, regular security assessments, and user education programs to reduce the attack surface and prevent successful exploitation of similar vulnerabilities in their communication infrastructure.