CVE-2015-1639 in Office
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Microsoft Office for Mac 2011 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka "Microsoft Outlook App for Mac XSS Vulnerability."
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Analysis
by VulDB Data Team • 05/06/2022
The CVE-2015-1639 vulnerability represents a critical cross-site scripting flaw in Microsoft Office for Mac 2011 that exposes users to remote code execution risks through web script injection. This vulnerability specifically affects the Outlook application component within the Microsoft Office suite for macOS, creating a pathway for attackers to exploit user interactions with maliciously crafted content. The vulnerability stems from insufficient input validation and output encoding mechanisms within the email rendering engine, allowing malicious scripts to execute in the context of the user's browser session when processing infected email messages.
The technical implementation of this XSS vulnerability occurs through unspecified vectors that likely involve the processing of HTML content within email messages. Attackers can craft malicious emails containing crafted HTML tags or JavaScript code that gets executed when the recipient opens the email in Outlook for Mac. This flaw operates under CWE-79 which classifies cross-site scripting as a weakness that allows attackers to inject malicious scripts into web applications viewed by other users. The vulnerability's impact is amplified because it affects a widely used productivity application that users trust and interact with regularly, making social engineering attacks more effective.
From an operational perspective, this vulnerability creates significant risk for enterprise environments where Microsoft Office for Mac 2011 is deployed. The attack surface includes email servers, user workstations, and any system that processes Outlook email messages containing malicious content. The vulnerability enables attackers to perform session hijacking, steal user credentials, redirect users to malicious websites, or execute arbitrary code on affected systems. According to ATT&CK framework, this vulnerability maps to T1059.007 for scripting and T1566 for phishing techniques, as attackers can leverage this flaw to create more convincing phishing campaigns that bypass traditional email filtering mechanisms.
Organizations should implement immediate mitigations including patching the vulnerability through Microsoft security updates, implementing email filtering solutions that detect and block suspicious HTML content, and establishing user awareness training programs to recognize potentially malicious email messages. Network segmentation and web application firewalls can provide additional layers of protection by monitoring and filtering traffic containing known malicious patterns. The vulnerability also highlights the importance of maintaining up-to-date security patches across all Microsoft Office applications, as similar flaws may exist in other components of the Office suite. Security teams should conduct vulnerability assessments to identify systems running the affected Office version and prioritize remediation efforts based on risk exposure levels.