CVE-2014-4148
Microsoft Windows Remote Code Execution Vulnerability
Description
CVE-2014-4148 is a remote code execution vulnerability in the Windows kernel-mode driver caused by improper handling of TrueType fonts. When the Windows kernel-mode driver processes a specially crafted TrueType font, the improper handling leads to memory corruption that allows an attacker to execute arbitrary code with kernel-level privileges. This Windows kernel font vulnerability can be exploited through web pages, documents, or any content that embeds custom fonts. CISA has listed CVE-2014-4148 in the Known Exploited Vulnerabilities catalog, confirming active exploitation, and its EPSS percentile of 97.9% indicates near-certain exploitation activity.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 7 | - |
| microsoft | windows 8 | - |
| microsoft | windows 8.1 | - |
| microsoft | windows rt | - |
| microsoft | windows rt 8.1 | - |
| microsoft | windows server 2003 | - |
| microsoft | windows server 2008 | -; r2 |
| microsoft | windows server 2012 | -; r2 |
| microsoft | windows vista | - |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://blogs.technet.com/b/srd/archive/2014/10/14/accessing-risk-for-the-october-2014-security-updates.aspx(Not Applicable)
- http://secunia.com/advisories/60970(Broken Link)
- http://www.securityfocus.com/bid/70429(Broken Link, Third Party Advisory, VDB Entry)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-058(Patch, Vendor Advisory)
- https://exchange.xforce.ibmcloud.com/vulnerabilities/96995(Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2014-4148(US Government Resource)
Weakness Type
No specific CWE has been assigned to CVE-2014-4148 in the NVD database. The vulnerability involves improper handling of TrueType font data in the Windows kernel-mode driver (win32k.sys). When processing crafted font files, the kernel-mode font rendering engine fails to properly validate font data structures, leading to kernel memory corruption. Because font rendering in affected Windows versions occurs in kernel mode, this flaw enables code execution at the highest privilege level (Ring 0), making it significantly more dangerous than user-mode font rendering vulnerabilities.
Learn more: CWE Overview
Impact Analysis
CVE-2014-4148 allows remote code execution with kernel-level privileges through the Windows kernel-mode driver's font handling. The vulnerability is remotely exploitable through any content containing crafted TrueType fonts, including web pages and documents. Confidentiality (High): Kernel-level code execution grants the attacker unrestricted access to all system data, including protected kernel memory, all user credentials, and encrypted data accessible through kernel-level keys. Integrity (High): With kernel privileges, the attacker can modify any file on the system, install rootkits that persist at the deepest system level, and manipulate any kernel data structure. Availability (High): The attacker can render the system completely inoperable, corrupt the file system, or deploy destructive payloads. With an EPSS percentile of 97.9%, this vulnerability has near-certain exploitation activity. The kernel-level execution context makes this exceptionally severe, as the attacker gains the highest possible privilege level.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2014-4148 by listing it in the Known Exploited Vulnerabilities catalog, with a remediation deadline of June 15, 2022. The EPSS percentile of 97.9% indicates near-certain exploitation activity. Kernel-mode font rendering vulnerabilities in Windows have been exploited in sophisticated targeted attacks, including state-sponsored campaigns. The ability to achieve kernel-level code execution through a remotely-delivered font file makes this vulnerability exceptionally valuable for advanced persistent threat (APT) groups seeking deep system access for espionage or destructive purposes.
Remediation
- Apply Microsoft security updates per vendor instructions as required by the CISA KEV catalog. Install all relevant patches that address CVE-2014-4148 in the Windows kernel-mode driver.
- Upgrade to a modern, supported version of Windows that has moved font rendering out of the kernel into a user-mode sandbox. Windows 10 and later versions significantly reduce the impact of font parsing vulnerabilities by processing fonts in a restricted user-mode context.
- Block untrusted font loading using the Group Policy setting "Untrusted Font Blocking" available in Windows 10 and later, which prevents loading fonts from outside the trusted fonts directory.
- Deploy web content filtering and email security to detect and block content containing suspicious embedded TrueType fonts before they reach end users.
- Monitor for kernel-level exploitation indicators including unexpected kernel crashes (BSODs), unusual kernel-mode driver behavior, and system integrity violations that may indicate kernel rootkit installation.
Technical Details
CVE-2014-4148 is a kernel-mode memory corruption vulnerability in the Windows TrueType font rendering engine. In affected Windows versions, the font rendering pipeline processes TrueType font data through the win32k.sys kernel-mode driver. When a malformed TrueType font with corrupted table entries is processed, the kernel-mode parser fails to properly validate the data, resulting in out-of-bounds memory access in kernel space. This kernel memory corruption can be exploited to overwrite kernel data structures, redirect function pointers, or corrupt page table entries, ultimately enabling the attacker to execute arbitrary code at Ring 0 (kernel) privilege level. The attack vector is particularly dangerous because font rendering is triggered automatically when any application displays text using a custom font, meaning the victim only needs to view a web page or open a document containing the malicious font. The kernel-mode execution context means successful exploitation bypasses all user-mode security mechanisms.
Frequently Asked Questions
Is CVE-2014-4148 being actively exploited?
Yes, CVE-2014-4148 is actively exploited. CISA confirmed its inclusion in the Known Exploited Vulnerabilities catalog with a remediation deadline of June 15, 2022. The EPSS percentile of 97.9% indicates near-certain exploitation activity, with documented use in sophisticated targeted attacks.
What products are affected by CVE-2014-4148?
CVE-2014-4148 affects Microsoft Windows through the kernel-mode driver (win32k.sys) that handles TrueType font rendering. Multiple Windows versions are affected where font rendering occurs in kernel mode.
How do I fix CVE-2014-4148?
Apply Microsoft security patches addressing this vulnerability. Upgrade to Windows 10 or later, which processes fonts in a user-mode sandbox rather than the kernel. Enable untrusted font blocking through Group Policy and deploy content filtering to block malicious font content.
How severe is CVE-2014-4148?
CVE-2014-4148 is a remote code execution vulnerability with kernel-level execution and an EPSS percentile of 97.9%. The combination of remote exploitability through web content and kernel-level code execution makes this one of the most severe classes of Windows vulnerabilities, enabling complete system compromise through simply viewing a web page or document.
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