CVE-2016-0117 in Windows
Summary
by MITRE
The PDF library in Microsoft Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 allows remote attackers to execute arbitrary code via a crafted PDF document, aka "Windows Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 07/09/2022
The vulnerability identified as CVE-2016-0117 represents a critical remote code execution flaw within the PDF library component of several Microsoft Windows operating systems including Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511. This vulnerability resides in the way these systems process PDF documents, specifically in the parsing and rendering mechanisms that handle embedded objects within PDF files. The flaw enables malicious actors to craft specially designed PDF documents that, when opened by vulnerable systems, can trigger arbitrary code execution on the target machine without requiring user interaction beyond opening the document. This represents a significant security risk as PDF documents are commonly encountered in email attachments, web downloads, and document sharing scenarios, making the attack surface particularly broad.
The technical nature of this vulnerability stems from improper input validation and memory handling within the PDF processing library. When a vulnerable system attempts to parse a crafted PDF document, the malicious payload embedded within the document can exploit buffer overflows, memory corruption issues, or other parsing errors that occur during the interpretation of PDF elements such as embedded scripts, fonts, or graphics objects. The underlying flaw typically manifests as insufficient bounds checking or improper memory management during the parsing process, allowing attackers to overwrite memory locations or redirect program execution flow. This vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read vulnerabilities. The attack vector operates through the standard PDF rendering pipeline that Windows uses to display PDF content, making it particularly dangerous as users cannot easily distinguish between legitimate and malicious PDF documents.
The operational impact of CVE-2016-0117 extends far beyond simple remote code execution, as successful exploitation can result in complete system compromise. Attackers can leverage this vulnerability to install malware, establish backdoors, exfiltrate sensitive data, or perform further lateral movement within network environments. The vulnerability affects enterprise environments particularly severely since PDF documents are frequently used in business communications and document management systems. Organizations running affected Windows versions face significant risk of unauthorized access and data breaches when users inadvertently open malicious PDF files. The exploitability of this vulnerability is relatively high due to the widespread use of PDF documents and the fact that the attack requires minimal user interaction beyond opening the document, making it particularly dangerous for phishing campaigns and targeted attacks. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as successful exploitation often leads to elevated privileges and persistent access.
Microsoft addressed this vulnerability through security updates released in their regular monthly patch cycle, specifically including fixes for the PDF library component that mitigates the memory corruption issues. Organizations should prioritize applying these security updates immediately to protect their systems from exploitation. Additionally, implementing defense-in-depth strategies such as PDF sandboxing, email filtering for suspicious attachments, and network-based content filtering can provide additional protection layers. Security teams should monitor for indicators of compromise related to this vulnerability, including unusual network connections or file creation patterns that might indicate exploitation attempts. The vulnerability also underscores the importance of keeping all system components updated, as PDF processing libraries are frequently targeted by attackers due to their widespread use and the complexity of the underlying parsing processes. Network administrators should consider implementing network segmentation and access controls to limit the potential impact of successful exploitation attempts, particularly in environments where users have broad access to PDF documents from external sources.