CVE-2015-1650 in Office
Summary
by MITRE
Use-after-free vulnerability in Microsoft Word 2007 SP3, Office 2010 SP2, Word 2010 SP2, Word 2013 SP1, Word 2013 RT SP1, Word Viewer, Office Compatibility Pack SP3, Word Automation Services on SharePoint Server 2010 SP2 and 2013 SP1, and Office Web Apps Server 2010 SP2 and 2013 SP1 allows remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Component Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 05/06/2022
This vulnerability represents a critical use-after-free flaw in Microsoft Office components that affects multiple versions of Word and related applications. The vulnerability occurs when the Office application processes maliciously crafted Office documents, specifically exploiting memory management issues where freed memory locations are still accessed by subsequent operations. The flaw exists within the Office component responsible for handling document parsing and rendering, creating a scenario where an attacker can manipulate memory state to achieve arbitrary code execution. This type of vulnerability falls under the CWE-416 category for use-after-free conditions, which is a well-documented and dangerous class of memory corruption vulnerabilities that have been exploited extensively in the wild.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass full system compromise capabilities. Attackers can leverage this flaw by delivering malicious Office documents through various attack vectors including email attachments, web downloads, or compromised websites. When a user opens the crafted document, the vulnerable Office component triggers the use-after-free condition, allowing the attacker to inject and execute malicious code with the privileges of the compromised user. This vulnerability has been actively exploited in the wild, making it particularly dangerous for enterprise environments where Office documents are commonly shared and opened. The attack chain typically involves crafting a malicious document that when processed by the vulnerable Office application causes memory corruption, which can then be leveraged to gain arbitrary code execution.
The technical exploitation requires precise control over memory layout and execution flow within the Office application. Attackers typically construct documents with carefully crafted structures that, when parsed by the vulnerable components, result in freed memory being accessed again. This process often involves manipulating object references and memory allocation patterns to ensure successful exploitation. The vulnerability affects not only standalone Office installations but also server-side components including SharePoint Server 2010 and 2013, as well as Office Web Apps Server, making it particularly dangerous for enterprise environments where these components are widely deployed. Organizations running these affected versions face significant risk as the vulnerability can be exploited without user interaction in some scenarios, making it a preferred target for advanced persistent threats. The ATT&CK framework categorizes this type of vulnerability under T1059 for command and scripting interpreter and T1190 for exploit for client execution, highlighting the multi-stage nature of exploitation that includes initial access through document delivery followed by execution of malicious payloads.
Mitigation strategies for this vulnerability include immediate application of Microsoft security patches and updates, which address the underlying memory management issues in the affected Office components. Organizations should implement strict document validation policies and user education programs to reduce exposure to malicious documents. Network-level controls such as email filtering and web proxy configurations can help prevent delivery of malicious Office documents to end users. Additionally, implementing application whitelisting policies and using Office's built-in security features like Protected View can provide additional layers of defense. The vulnerability also underscores the importance of maintaining up-to-date security patches across all Office installations, including server components, as the affected versions span multiple product lines and deployment scenarios. Regular security assessments and vulnerability scanning should be conducted to identify and remediate any remaining instances of the vulnerable software versions.