CVE-2017-8743 in PowerPoint
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft PowerPoint 2016, Microsoft SharePoint Enterprise Server 2016, and Office Online Server when they fail to properly handle objects in memory, aka "PowerPoint Remote Code Execution Vulnerability". This CVE ID is unique from CVE-2017-8742.
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Analysis
by VulDB Data Team • 01/12/2021
The vulnerability described in CVE-2017-8743 represents a critical remote code execution flaw affecting multiple Microsoft Office and SharePoint products, specifically targeting PowerPoint 2016, SharePoint Enterprise Server 2016, and Office Online Server. This vulnerability stems from improper memory handling during object processing, creating a pathway for attackers to execute arbitrary code on affected systems. The flaw exists in the way these applications process certain file formats, particularly those containing specially crafted malicious objects that trigger memory corruption conditions. The vulnerability is classified under CWE-125, which represents an out-of-bounds read condition, and aligns with ATT&CK technique T1203, involving legitimate credentials and privilege escalation through remote access.
The technical exploitation of this vulnerability occurs when a user opens a specially crafted PowerPoint file or interacts with malicious content within SharePoint or Office Online environments. The memory handling error manifests when the application attempts to process malformed objects within presentation files, leading to buffer overflows or memory corruption that can be leveraged by attackers to inject and execute malicious code. Attackers can craft documents containing malicious code that, when processed by the vulnerable applications, triggers the memory corruption and allows for arbitrary code execution with the privileges of the affected user. This vulnerability is particularly dangerous because it can be exploited through social engineering techniques, where users are tricked into opening malicious files, or through compromised SharePoint servers that serve malicious content to unsuspecting users.
The operational impact of CVE-2017-8743 extends beyond individual user systems to enterprise environments where SharePoint and Office Online servers serve as central collaboration platforms. Organizations running affected versions of Microsoft Office and SharePoint are at risk of complete system compromise, data exfiltration, and potential lateral movement within networks. The vulnerability's remote execution capability means that attackers do not require physical access to target systems, making it particularly attractive for large-scale attacks. The exploitation can result in persistent backdoors, credential theft, and establishment of command and control channels. This vulnerability also represents a significant risk to organizations that rely heavily on Office Online Server for document collaboration, as it can be exploited through web-based attacks without requiring users to download files locally.
Mitigation strategies for CVE-2017-8743 should include immediate deployment of Microsoft security patches and updates, particularly the July 2017 security updates that specifically address this vulnerability. Organizations should implement strict file validation and filtering mechanisms, particularly for files received through email or shared storage systems. Network segmentation and access controls can help limit the potential impact of successful exploitation by restricting lateral movement within affected networks. Security awareness training should be enhanced to help users recognize potentially malicious files and avoid opening suspicious attachments or links. The implementation of application whitelisting and sandboxing technologies can provide additional protection layers against exploitation attempts. Organizations should also monitor network traffic for signs of exploitation attempts and implement intrusion detection systems that can identify anomalous behavior associated with memory corruption attacks. Regular security assessments and vulnerability scanning should be conducted to ensure that all affected systems are properly patched and that no additional vulnerabilities exist in the environment.