CVE-2017-11224 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 use after free vulnerability in the XFA layout engine. 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-2017-11224 represents a critical use after free flaw within Adobe Acrobat Reader's XFA layout engine, affecting multiple versions of the software including 2017.009.20058 and earlier, 2017.008.30051 and earlier, 2015.006.3030306 and earlier, and 11.0.20 and earlier. This vulnerability resides in the XFA (XML Forms Architecture) processing component that handles complex form layouts and data binding operations. The XFA engine is responsible for rendering interactive PDF forms that contain dynamic content and complex formatting, making it a prime target for exploitation due to the extensive processing required for form manipulation and display. The flaw manifests when the application improperly handles memory management during the processing of XFA elements, leading to situations where freed memory blocks are still accessed or reused by subsequent operations.
The technical nature of this vulnerability aligns with CWE-416, which describes the use after free condition where memory is accessed after it has been freed, and may also relate to CWE-122, which covers heap-based buffer overflows. The exploitation occurs when an attacker crafts a malicious PDF document containing specially constructed XFA elements that trigger the flawed memory management behavior. During normal operation, the XFA engine allocates memory for form elements and processes them through various layout calculations. However, when encountering malformed XFA structures, the engine fails to properly track memory references, allowing freed memory to be accessed or overwritten by subsequent operations. This creates a scenario where an attacker can control the contents of freed memory blocks and potentially manipulate program execution flow through carefully crafted input data.
The operational impact of this vulnerability extends beyond simple privilege escalation or denial of service, as successful exploitation can result in arbitrary code execution with the privileges of the user running Acrobat Reader. This represents a significant threat in enterprise environments where users frequently open PDF documents from untrusted sources, including email attachments, web downloads, and file sharing platforms. The attack vector typically involves social engineering campaigns where users are诱导 to open malicious PDF files containing the crafted XFA structures. The vulnerability's exploitation potential makes it particularly dangerous for targeted attacks against high-value targets such as executives, security professionals, or individuals in sensitive roles. The XFA engine's complex processing requirements and the large attack surface it provides make this vulnerability particularly attractive to threat actors seeking persistent access to systems. Additionally, the widespread adoption of Adobe Acrobat Reader across various industries and platforms amplifies the potential impact of successful exploitation.
Organizations should implement immediate mitigations including mandatory software updates to the latest versions of Adobe Acrobat Reader where the vulnerability has been patched, along with network-based controls such as PDF file filtering at perimeter defenses. The implementation of sandboxing technologies for PDF processing can provide additional layers of protection by isolating potentially malicious content from the primary system environment. Security teams should also deploy email filtering solutions that can detect and block suspicious PDF attachments containing known malicious patterns, while monitoring for unusual PDF processing behavior that might indicate exploitation attempts. User education programs should emphasize the importance of only opening PDF files from trusted sources and avoiding suspicious email attachments. The mitigation strategy should also include regular vulnerability assessments and penetration testing to identify systems that may still be running vulnerable versions of the software. Organizations should consider implementing application whitelisting policies that restrict execution of untrusted PDF processing software, and maintain comprehensive incident response procedures that can quickly address potential exploitation attempts. Additionally, monitoring for indicators of compromise related to PDF-based attacks, including unusual network connections or file access patterns, can help detect exploitation attempts before they result in successful compromises.