CVE-2017-2949 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat Reader versions 15.020.20042 and earlier, 15.006.30244 and earlier, 11.0.18 and earlier have an exploitable heap overflow vulnerability in the XSLT engine. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 10/28/2022
The vulnerability identified as CVE-2017-2949 represents a critical heap overflow condition within Adobe Acrobat Reader's XSLT processing engine, affecting multiple version ranges including 15.020.20042 and earlier, 15.006.30244 and earlier, and 11.0.18 and earlier. This flaw exists in the way the software handles XSLT transformations, which are commonly used for converting xml data into other formats such as html or text. The heap overflow occurs when the application processes maliciously crafted XSLT files that contain oversized or malformed data structures, leading to memory corruption that can be exploited by attackers.
The technical nature of this vulnerability places it under CWE-121, heap-based buffer overflow, which is a well-documented class of memory safety issues that have been the primary target of exploitation techniques for decades. When an attacker crafts a malicious XSLT file with oversized data elements or malformed processing instructions, the XSLT engine fails to properly validate input boundaries, allowing memory allocation to exceed intended limits. This memory corruption can result in overwriting adjacent memory locations, potentially including return addresses, function pointers, or other critical control data structures within the application's execution context.
From an operational perspective, the impact of this vulnerability extends beyond simple code execution as it provides attackers with a pathway to achieve complete system compromise. The exploitability of this heap overflow means that an attacker could potentially execute arbitrary code with the privileges of the victim user, making it particularly dangerous in enterprise environments where users may have elevated permissions. The vulnerability is especially concerning because XSLT processing is commonly used in PDF documents for dynamic content generation, making it a natural target for attackers who might embed malicious XSLT code within seemingly legitimate documents.
The attack surface for this vulnerability is broad given that Adobe Acrobat Reader is widely deployed across organizations and individuals for viewing PDF documents. Attackers could deliver malicious payloads through phishing emails containing infected PDF documents, or through compromised websites that serve malicious content. The exploit typically requires user interaction to open the malicious PDF, making social engineering a critical component of successful attacks. This vulnerability aligns with ATT&CK technique T1203, Exploitation for Client Execution, which describes how adversaries leverage application vulnerabilities to execute code on targeted systems. The attack chain would involve delivering a crafted PDF with malicious XSLT content, which when opened by the vulnerable Acrobat Reader application, triggers the heap overflow and subsequent code execution.
Organizations should prioritize immediate remediation through patch management procedures, as Adobe released security updates addressing this vulnerability in subsequent versions of Acrobat Reader. The mitigation strategy should include comprehensive network monitoring for suspicious PDF file deliveries and user behavior analysis to detect potential exploitation attempts. Additionally, implementing application whitelisting policies that restrict execution of untrusted PDF files, combined with regular security awareness training for users, can significantly reduce the risk of successful exploitation. The vulnerability also highlights the importance of input validation and memory safety practices in software development, particularly for applications that process structured data formats like XML and XSLT, which are increasingly common in enterprise document processing workflows.