CVE-2017-11214 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat Reader 2017.009.20058 and earlier, 2017.008.30051 and earlier, 2015.006.30306 and earlier, and 11.0.20 and earlier has an exploitable memory corruption vulnerability in the image conversion engine when processing Enhanced Metafile Format (EMF) data related to rendering a path. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 08/29/2024
This vulnerability resides within Adobe Acrobat Reader's image conversion engine, specifically when processing Enhanced Metafile Format (EMF) data during path rendering operations. The flaw represents a classic memory corruption vulnerability that can be exploited through crafted EMF files, allowing attackers to execute arbitrary code on affected systems. The vulnerability affects multiple versions of Adobe Acrobat Reader spanning from 2017.009.20058 and earlier down to version 11.0.20, indicating a long-standing issue that persisted across several major releases. The memory corruption occurs in the image conversion engine's handling of EMF data, which is a vector commonly used in Office documents and other applications for vector graphics rendering. This type of vulnerability falls under the category of heap-based buffer overflows as described in CWE-122, where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The exploitation mechanism leverages the path rendering functionality within EMF processing, which is a legitimate feature used to display vector graphics but becomes dangerous when input data is malformed or maliciously crafted. The vulnerability's impact is significant as it allows for remote code execution without requiring user interaction beyond opening a malicious document, making it particularly dangerous in phishing campaigns or targeted attacks. Attackers can craft specially designed EMF files that trigger the memory corruption when the affected software attempts to render them, potentially leading to full system compromise.
The technical implementation of this vulnerability involves the improper handling of memory allocation and deallocation within the image conversion engine's EMF processing pipeline. When Acrobat Reader encounters an EMF file containing a specially crafted path element, the conversion engine fails to properly validate the input data before processing it, leading to memory corruption that can be leveraged for code execution. This vulnerability aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries exploit software vulnerabilities to execute malicious code on target systems. The flaw demonstrates a lack of proper input validation and memory management practices, which are fundamental security requirements in software development. The path rendering component of EMF processing is particularly susceptible because it involves complex mathematical calculations and memory operations that can be manipulated through carefully crafted input parameters. The vulnerability's exploitability is enhanced by the fact that EMF files can be embedded in various document formats, including pdf files, making it easier for attackers to deliver malicious payloads through seemingly legitimate documents. The memory corruption occurs during the conversion process where the software attempts to transform EMF data into a format suitable for display, creating opportunities for attackers to inject malicious code into the execution flow.
The operational impact of this vulnerability extends beyond simple code execution to potentially enable full system compromise and persistent access. Once successfully exploited, attackers can gain the same privileges as the user running Acrobat Reader, which often includes administrative rights on the system. The vulnerability's presence in multiple versions of Acrobat Reader makes it particularly dangerous as it affects both older legacy systems and newer deployments that may not have received timely security updates. Organizations using Acrobat Reader for document processing, especially in environments where users open documents from untrusted sources, face significant risk from this vulnerability. The nature of EMF files as vector graphics formats means they can be embedded in various file types, including pdf documents, making the attack surface broader than initially apparent. This vulnerability can be particularly problematic in enterprise environments where Acrobat Reader is widely deployed and users frequently open documents from external sources. The lack of user interaction required for exploitation makes it ideal for automated attack campaigns, where adversaries can send malicious documents through email or other communication channels without needing to trick users into performing specific actions. The vulnerability's classification as a remote code execution flaw means that attackers can compromise systems without physical access or direct user involvement, making it a critical concern for network security. Security professionals must consider the broader implications of this vulnerability when assessing their attack surface and implementing defensive measures against similar memory corruption flaws. The vulnerability also highlights the importance of keeping software updated and implementing proper input validation controls in all applications that process external data. Organizations should implement network segmentation and access controls to limit the potential impact of successful exploitation, while also ensuring that Acrobat Reader is regularly updated with the latest security patches to prevent attackers from leveraging this known vulnerability.