CVE-2017-11241 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 heap overflow vulnerability in the image conversion engine when processing Enhanced Metafile Format (EMF) data related to polygons. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 08/30/2024
The vulnerability identified as CVE-2017-11241 represents a critical heap overflow flaw within Adobe Acrobat Reader's image processing capabilities, specifically affecting multiple versions of the software across different release cycles. This vulnerability resides in the Enhanced Metafile Format EMF image conversion engine, which is responsible for handling vector graphics and bitmap conversions within the PDF rendering pipeline. The flaw manifests when processing EMF data structures that contain polygon elements, making it particularly dangerous as polygon data is commonly used in professional document formatting and graphics rendering. The heap overflow condition occurs during the memory allocation and data processing phases when the application fails to properly validate the size and structure of incoming EMF polygon data, creating opportunities for malicious actors to manipulate memory layout and execute arbitrary code. This vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the heap-based nature of the flaw makes it particularly insidious in memory management contexts.
The technical exploitation of this vulnerability requires an attacker to craft a malicious PDF document containing specially constructed EMF data with oversized polygon structures that trigger the heap overflow condition. When a user opens such a document, the Acrobat Reader application processes the EMF data through its image conversion engine, leading to memory corruption that can be leveraged to overwrite critical memory regions including return addresses and function pointers. The exploitation mechanism aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation typically involves executing shellcode within the application's memory space. The vulnerability's impact is amplified by the widespread use of Adobe Acrobat Reader across enterprise environments, making it an attractive target for attackers seeking persistent access to organizational networks. The heap overflow allows for potential privilege escalation if the application runs with elevated permissions, though the primary threat vector remains remote code execution within the context of the vulnerable application.
The operational impact of CVE-2017-11241 extends beyond immediate code execution capabilities to encompass broader security implications for document handling environments. Organizations relying on Acrobat Reader for document review and processing face significant risk exposure, as the vulnerability can be triggered through simple document opening without requiring user interaction beyond normal application usage. The vulnerability affects multiple product versions, indicating a systemic issue within the image processing subsystem that was not adequately addressed in the software's security architecture. Network-based attacks leveraging this vulnerability can occur through email attachments, web downloads, or document sharing platforms, making traditional network segmentation less effective as a protective measure. The exploitation requires minimal user interaction beyond opening the malicious document, which aligns with ATT&CK tactic T1203 for exploitation for privilege escalation and T1190 for exploitation of remote services, demonstrating the vulnerability's suitability for automated attack campaigns.
Mitigation strategies for CVE-2017-11241 should prioritize immediate patch management and application hardening measures. Adobe released security updates addressing this vulnerability in subsequent versions of Acrobat Reader, making patch deployment the primary defensive measure. Organizations should implement strict document filtering policies that prevent the automatic execution of embedded objects and images, particularly those originating from untrusted sources. Network security controls should include content inspection for PDF files, especially when they originate from external sources or contain embedded image data. The vulnerability's exploitation requires no user interaction beyond opening a document, making it particularly dangerous for organizations with limited security awareness training. Security monitoring should focus on unusual Acrobat Reader processes and memory access patterns that might indicate exploitation attempts. Additionally, implementing application whitelisting for Acrobat Reader and restricting its capabilities through sandboxing or virtualization can provide additional protection layers, though these measures should complement rather than replace proper patch management. The vulnerability demonstrates the importance of maintaining up-to-date software and implementing defense-in-depth strategies to protect against zero-day exploits that target widely used applications.