CVE-2018-8636 in Excel
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory, aka "Microsoft Excel Remote Code Execution Vulnerability." This affects Office 365 ProPlus, Microsoft Office, Microsoft Excel. This CVE ID is unique from CVE-2018-8597.
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Analysis
by VulDB Data Team • 06/18/2023
The vulnerability identified as CVE-2018-8636 represents a critical remote code execution flaw within Microsoft Excel software that stems from improper handling of objects in memory. This vulnerability specifically affects Microsoft Office 365 ProPlus, Microsoft Office, and Microsoft Excel across multiple versions, making it a widespread concern for organizations relying on these productivity suites. The flaw allows attackers to execute arbitrary code on targeted systems without requiring user interaction, creating a severe threat vector for cybercriminals seeking to compromise enterprise environments. The vulnerability's classification as a remote code execution issue places it within the purview of attack vectors that can be exploited over networks without physical access to target systems.
The technical root cause of CVE-2018-8636 lies in the memory management mechanisms within Excel's object handling processes. When Excel processes certain file formats or objects within spreadsheets, it fails to properly validate or sanitize memory references, leading to potential buffer overflows or memory corruption scenarios. This type of vulnerability typically manifests when maliciously crafted files are opened by vulnerable applications, allowing attackers to manipulate memory pointers and execute malicious code with the privileges of the targeted user. The flaw operates at the memory management level, making it particularly dangerous as it can bypass many traditional security controls that focus on network-level or user-input validation.
From an operational impact perspective, this vulnerability poses significant risks to enterprise security posture and business continuity. Organizations with extensive Excel usage patterns face heightened exposure since the attack vector requires only a single malicious file to be opened, which could occur through email attachments, web downloads, or file sharing platforms. The remote execution capability means that attackers can compromise systems from anywhere in the world, potentially leading to data breaches, system takeovers, or lateral movement within networks. Security teams must consider the cascading effects of such vulnerabilities, as successful exploitation could provide attackers with persistent access to sensitive corporate data and infrastructure. The vulnerability's presence in widely deployed Office suites makes it particularly attractive to threat actors seeking broad impact with minimal effort.
Mitigation strategies for CVE-2018-8636 should prioritize immediate patch management and implementation of defensive measures. Microsoft released security updates that address this vulnerability through proper memory handling and validation mechanisms, requiring organizations to apply these patches promptly across all affected systems. Network segmentation and email filtering controls can provide additional layers of protection by preventing malicious files from reaching end users. The implementation of application whitelisting policies can restrict execution of unauthorized Office applications or file formats that might trigger the vulnerability. Security monitoring should focus on anomalous file opening patterns and memory access behaviors that could indicate exploitation attempts. Organizations should also consider disabling automatic opening of files from untrusted sources and implementing user awareness training to reduce the likelihood of successful social engineering attacks that leverage this vulnerability. This vulnerability aligns with CWE-125, which addresses out-of-bounds read conditions, and represents a significant concern under ATT&CK technique T1203, which covers Exploitation for Client Execution, emphasizing the importance of addressing memory corruption vulnerabilities in productivity software applications.