CVE-2018-8248 in Office
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 Microsoft Office.
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Analysis
by VulDB Data Team • 03/27/2023
The vulnerability identified as CVE-2018-8248 represents a critical remote code execution flaw within Microsoft Excel software that stems from improper handling of objects in memory. This vulnerability specifically impacts Microsoft Office products and enables attackers to execute arbitrary code on affected systems. The flaw occurs when Excel processes certain file formats or objects that trigger memory corruption conditions, allowing malicious actors to gain unauthorized access and control over vulnerable systems. The vulnerability is particularly concerning because it can be exploited remotely through various attack vectors including email attachments, malicious websites, or compromised documents. Security researchers have classified this as a remote code execution vulnerability due to its ability to allow attackers to run malicious code with the privileges of the targeted user, potentially leading to complete system compromise and data exfiltration.
The technical root cause of CVE-2018-8248 lies in the improper memory management practices within Excel's object handling mechanisms. When Excel processes malformed or specially crafted objects within spreadsheet files, the application fails to validate memory boundaries properly, leading to memory corruption that can be leveraged by attackers. This type of vulnerability falls under the CWE-125 vulnerability category, which describes out-of-bounds read conditions that occur when software reads data from memory locations beyond the intended buffer boundaries. The flaw typically manifests when Excel attempts to parse complex spreadsheet objects or formulas that contain malicious data structures, causing the application to allocate or access memory in unexpected ways. Attackers can craft specific Excel files that trigger these memory handling issues, resulting in controlled execution of arbitrary code within the context of the running Excel process.
The operational impact of this vulnerability extends far beyond simple exploitation, as it enables attackers to perform sophisticated cyber operations including persistent system compromise, data theft, and lateral movement within network environments. Organizations using affected versions of Microsoft Office are particularly vulnerable since the attack surface includes any user who might open malicious Excel files, whether through email phishing campaigns, malicious web downloads, or compromised file sharing systems. The remote execution capability means that attackers do not require physical access to target systems, making this vulnerability highly attractive for large-scale cyber attacks. Once successfully exploited, the vulnerability can provide attackers with complete control over the affected system, enabling them to install additional malware, establish backdoors, and access sensitive corporate or personal data. The widespread use of Microsoft Excel across enterprise environments amplifies the potential impact of this vulnerability, as a single compromised user can potentially affect entire organizations.
Mitigation strategies for CVE-2018-8248 should encompass both immediate patching and operational security measures to reduce risk exposure. Microsoft released security updates that address this vulnerability through patches to Microsoft Office applications, which organizations should deploy immediately to protect their systems. The recommended approach includes implementing timely security updates, configuring application whitelisting policies to restrict execution of untrusted Office files, and deploying email filtering solutions to prevent malicious attachments from reaching users. Network segmentation and monitoring solutions should be employed to detect suspicious file access patterns or attempts to execute malicious code. Security teams should also implement user education programs to reduce the risk of social engineering attacks that often deliver malicious Excel files through phishing campaigns. Additionally, organizations should consider implementing endpoint protection solutions that can detect and block known malicious file patterns or behaviors associated with this vulnerability, while maintaining regular security assessments to identify potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under the execution and privilege escalation tactics, emphasizing the need for comprehensive defensive measures that address both initial compromise and post-exploitation activities.