CVE-2018-8247 in Office Web Apps Server
Summary
by MITRE
An elevation of privilege vulnerability exists when Office Web Apps Server 2013 and Office Online Server fail to properly handle web requests, aka "Microsoft Office Elevation of Privilege Vulnerability." This affects Microsoft Office, Microsoft Office Online Server. This CVE ID is unique from CVE-2018-8245.
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Analysis
by VulDB Data Team • 03/27/2023
The vulnerability identified as CVE-2018-8247 represents a critical elevation of privilege flaw within Microsoft Office Web Apps Server 2013 and Office Online Server implementations. This weakness stems from the improper handling of web requests by these Microsoft Office server components, creating a security gap that malicious actors can exploit to gain elevated system privileges. The vulnerability specifically impacts organizations that rely on these server technologies for document processing and collaboration services, potentially allowing attackers to execute unauthorized code with higher privileges than initially granted.
The technical nature of this flaw lies in how the affected Microsoft Office server products process incoming web requests. When these systems receive malformed or specially crafted web requests, they fail to properly validate or sanitize the input before processing. This inadequate request handling creates a pathway for privilege escalation where an attacker could potentially leverage the vulnerability to execute arbitrary code with elevated privileges. The vulnerability operates at the server application level where web request processing logic does not adequately enforce security boundaries or validate request parameters, creating an attack surface that can be exploited to bypass normal access controls.
From an operational perspective, the impact of CVE-2018-8247 extends beyond simple privilege escalation to potentially compromise entire server infrastructures. Organizations utilizing Office Web Apps Server 2013 or Office Online Server face significant risk when this vulnerability is exploited, as successful exploitation could allow attackers to gain administrative access to document processing servers. This access could enable unauthorized modification of documents, data exfiltration, or the deployment of additional malware within the network. The vulnerability's impact is particularly concerning because it affects core collaboration and document processing services that many organizations depend upon for business operations.
The security implications align with CWE-20, which describes improper input validation, and can be mapped to ATT&CK technique T1068, which covers exploit for privilege escalation. Organizations should implement immediate mitigations including applying the relevant Microsoft security patches, implementing network segmentation to limit access to affected servers, and monitoring for suspicious web request patterns. Additionally, administrators should consider disabling unnecessary web services and implementing robust input validation mechanisms to prevent exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date security patches and proper server hardening practices to protect against sophisticated attack vectors targeting enterprise collaboration platforms.
This vulnerability demonstrates the critical importance of proper web request handling in server applications and highlights how seemingly minor input validation failures can create significant security risks. The affected Microsoft Office server products require careful monitoring and immediate remediation to prevent exploitation attempts. Security teams should prioritize this vulnerability in their risk assessment and remediation planning processes, particularly in environments where these server technologies are actively deployed and used for document collaboration and processing functions.