CVE-2017-11217 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 drawing of Unicode text strings. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 08/29/2024
This vulnerability resides in Adobe Acrobat Reader's image conversion engine which processes Enhanced Metafile Format data during Unicode text string rendering operations. The flaw manifests as a memory corruption issue that occurs when handling specific EMF data sequences containing Unicode text elements, creating a pathway for remote code execution. The vulnerability affects multiple versions spanning different release cycles including 2017.009.20058 and earlier, 2017.008.30051 and earlier, 2015.006.30306 and earlier, and 11.0.20 and earlier versions. The memory corruption vulnerability stems from improper bounds checking and memory management during the processing of EMF formatted data structures, particularly when these structures contain Unicode text strings that require conversion to rasterized formats.
The technical exploitation of this vulnerability follows a classic heap-based buffer overflow pattern where maliciously crafted EMF files can cause the application to write beyond allocated memory boundaries. When the image conversion engine encounters specific Unicode text string sequences within EMF data, it fails to properly validate input lengths and memory allocation sizes, leading to memory corruption that can be leveraged to execute arbitrary code. This type of vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a critical security flaw that allows attackers to bypass standard security mechanisms. The vulnerability operates at the intersection of graphics processing and memory management, where the conversion engine's handling of Unicode text in vector graphics formats creates an attack surface that can be exploited through crafted input files.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with persistent access to systems where Adobe Acrobat Reader is installed. Once successfully exploited, the attacker gains the ability to execute malicious code with the privileges of the user running the application, potentially leading to full system compromise. This vulnerability is particularly concerning in enterprise environments where Acrobat Reader is commonly used for document review and processing, as it can be triggered through email attachments or web downloads containing malicious EMF files. The exploitation mechanism aligns with ATT&CK technique T1203, Exploitation for Client Execution, and represents a significant threat vector for social engineering campaigns targeting document processing applications.
Mitigation strategies for this vulnerability require immediate patching of affected Adobe Acrobat Reader versions to address the underlying memory corruption issue in the image conversion engine. Organizations should implement strict file validation policies that prevent execution of untrusted EMF files, particularly those embedded in email attachments or downloaded from untrusted sources. Network-based mitigations can include filtering of EMF file types at perimeter defenses and implementing application whitelisting controls to restrict execution of vulnerable versions. Security teams should also monitor for indicators of compromise related to exploitation attempts, including unusual network connections or file execution patterns. The vulnerability demonstrates the importance of proper input validation and memory management in graphics processing libraries, highlighting the need for comprehensive security testing of rendering engines that handle complex vector graphics formats.