CVE-2018-0788 in Windows
Summary
by MITRE
The Windows Adobe Type Manager Font Driver (Atmfd.dll) in Windows 7 SP1, Windows 8.1 and RT 8.1, Windows Server 2008 SP2 and R2 SP1, and Windows Server 2012 and R2 allows an elevation of privilege vulnerability due to the way objects are handled in memory, aka "OpenType Font Driver Elevation of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 01/28/2021
The Windows Adobe Type Manager Font Driver vulnerability identified as CVE-2018-0788 represents a critical elevation of privilege flaw within Microsoft Windows operating systems. This vulnerability exists in the Atmfd.dll component which processes OpenType font files, specifically affecting Windows 7 SP1, Windows 8.1, RT 8.1, Windows Server 2008 SP2 and R2 SP1, and Windows Server 2012 and R2. The flaw stems from improper handling of memory objects during font processing operations, creating a pathway for malicious actors to escalate their privileges from standard user level to system level access.
The technical implementation of this vulnerability involves memory corruption issues within the Adobe Type Manager font driver's object handling mechanisms. When Windows processes certain malformed or specially crafted OpenType font files through the Atmfd.dll component, the driver fails to properly validate and manage memory allocations for font objects. This improper memory management creates exploitable conditions that can be leveraged to execute arbitrary code with elevated privileges. The vulnerability specifically relates to how the driver handles font data structures during rendering operations, where buffer overflows or use-after-free conditions may occur, allowing attackers to manipulate memory contents and gain unauthorized system access.
The operational impact of this vulnerability is severe as it enables attackers to achieve system-level compromise without requiring prior authentication. An attacker could exploit this vulnerability by enticing a user to open a malicious font file or by compromising a system through other means and then utilizing the font driver vulnerability to escalate privileges. Once successfully exploited, the attacker would gain complete control over the affected system, potentially allowing for data exfiltration, persistence mechanisms installation, or further network exploration. The vulnerability's presence across multiple Windows versions and server configurations increases its attack surface significantly, making it particularly dangerous in enterprise environments where various Windows versions may coexist.
Mitigation strategies for CVE-2018-0788 primarily involve applying Microsoft's security patches and updates, which address the underlying memory handling issues in the Atmfd.dll component. Organizations should prioritize patch deployment across all affected Windows systems, particularly those running the vulnerable server versions. Additional protective measures include implementing application whitelisting policies to restrict font file execution, disabling unnecessary font rendering capabilities, and monitoring for suspicious font-related activities in system logs. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and may map to ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation'. Organizations should also consider deploying endpoint protection solutions that can detect and block malicious font file execution patterns, as the vulnerability requires user interaction to be exploited, making user awareness and security controls crucial defensive measures.