CVE-2018-0855 in Windows
Summary
by MITRE
The Microsoft Windows Embedded OpenType (EOT) font engine in Microsoft Windows 7 SP1 and Windows Server 2008 R2 allows information disclosure, due to how the Windows EOT font engine handles embedded fonts, aka "Windows EOT Font Engine Information Disclosure Vulnerability". This CVE ID is unique from CVE-2018-0755, CVE-2018-0760, and CVE-2018-0761.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/18/2024
The vulnerability identified as CVE-2018-0855 represents a critical information disclosure flaw within the Microsoft Windows Embedded OpenType (EOT) font engine component. This vulnerability specifically affects Microsoft Windows 7 Service Pack 1 and Windows Server 2008 R2 systems, where the EOT font engine fails to properly handle embedded font data, creating potential security risks for affected environments. The issue stems from improper validation and processing of EOT font files that contain embedded content, allowing malicious actors to potentially extract sensitive information from the system. This vulnerability operates at the core font rendering layer of the Windows operating system, making it particularly dangerous as it can be exploited through seemingly benign font files that users might encounter during normal system operations.
The technical implementation of this vulnerability involves the EOT font engine's inadequate memory management and data handling procedures when processing specially crafted font files. When the Windows system attempts to render or process an EOT font containing maliciously constructed embedded data, the font engine's memory structures become corrupted or improperly accessed, leading to information disclosure. The flaw occurs during the font parsing phase where buffer overflows or improper memory boundaries are not properly enforced, allowing adjacent memory contents to be exposed to unauthorized access. This type of vulnerability typically falls under CWE-125, which describes out-of-bounds read conditions, and potentially CWE-787, describing out-of-bounds write conditions. The vulnerability enables attackers to potentially access sensitive data that should remain protected, including system memory contents, user credentials, or other confidential information stored in memory regions adjacent to the font processing code.
The operational impact of CVE-2018-0855 extends beyond simple information disclosure, as it can serve as a foundational vulnerability for more sophisticated attacks within the Windows environment. Attackers can leverage this vulnerability to gather system information that would aid in subsequent exploitation attempts, potentially enabling privilege escalation or lateral movement within networks. The vulnerability's presence in widely deployed operating systems like Windows 7 SP1 and Windows Server 2008 R2 means that organizations with legacy systems are particularly at risk, as these platforms continue to receive support from Microsoft through extended support periods. The exploitation of this vulnerability aligns with ATT&CK technique T1059, specifically focusing on the use of system utilities and services to execute malicious code, and may also map to T1068 which involves exploiting local privileges to gain system access. Organizations running these affected systems face potential exposure to attackers who could use this vulnerability to gather intelligence about system configurations, memory layouts, and other sensitive operational details.
Mitigation strategies for CVE-2018-0855 should prioritize immediate patch deployment through Microsoft's security updates, as the vulnerability has been addressed in subsequent security releases. System administrators should implement comprehensive monitoring of font processing activities and network traffic for suspicious patterns that might indicate exploitation attempts. The vulnerability can be mitigated through proper system hardening measures including disabling unnecessary font rendering capabilities, implementing strict file access controls, and employing application whitelisting solutions to prevent execution of potentially malicious font files. Additionally, organizations should consider implementing network segmentation to limit the potential impact of successful exploitation, ensuring that even if one system is compromised, attackers cannot easily move laterally through the network infrastructure. Regular security assessments and vulnerability scanning should include checks for the presence of vulnerable font engines and ensure that all systems are properly updated with the latest security patches. The implementation of security awareness training for users can also help reduce the risk of exploitation through social engineering attacks that might deliver malicious font files through email attachments or web downloads.