CVE-2017-3117 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 plugin that handles links within the PDF. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 01/08/2021
Adobe Acrobat Reader contains a critical heap overflow vulnerability in its PDF plugin handling mechanism that affects multiple versions including 2017.009.20058 and earlier, 2017.008.30051 and earlier, 2015.006.30306 and earlier, and 11.0.20 and earlier. This vulnerability resides within the plugin component responsible for processing hyperlinks and navigation elements within PDF documents, creating a pathway for malicious actors to execute arbitrary code on affected systems. The heap overflow occurs when the application fails to properly validate input data from malformed PDF link structures, allowing attackers to overwrite adjacent memory locations in the heap. This particular vulnerability maps to CWE-121 Heap-based Buffer Overflow, a well-documented weakness that enables attackers to manipulate program execution flow through memory corruption. The exploitability of this vulnerability is significantly enhanced by the fact that it requires no user interaction beyond opening a malicious PDF document, making it particularly dangerous in phishing campaigns and targeted attacks. Attackers can craft specially designed PDF files containing oversized or malformed link data that triggers the buffer overflow when the reader processes the document, potentially leading to complete system compromise. The operational impact extends beyond simple code execution as this vulnerability can be leveraged for privilege escalation, data exfiltration, and persistence mechanisms within compromised environments. Organizations using affected versions of Adobe Acrobat Reader face substantial risk given the widespread deployment of this software across enterprise networks, making it an attractive target for advanced persistent threat actors. The vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter, as successful exploitation enables attackers to execute arbitrary commands through the compromised application. This issue represents a critical security gap that directly impacts the integrity and confidentiality of sensitive information processed through PDF documents, particularly in environments where users frequently open documents from untrusted sources.
The technical flaw manifests when the PDF plugin attempts to parse link data structures without proper bounds checking, allowing an attacker to supply input that exceeds the allocated buffer size. Memory corruption occurs in the heap region where the plugin maintains link-related metadata, enabling attackers to overwrite critical program variables, function pointers, or return addresses. The vulnerability is particularly concerning due to the privileged execution context of Adobe Acrobat Reader, which often runs with elevated permissions when processing documents. This heap overflow can be exploited through various attack vectors including web-based delivery, email attachments, or malicious file sharing platforms where users might inadvertently open compromised PDF files. The exploitation process typically involves crafting a PDF document with carefully constructed link parameters that, when processed by the vulnerable plugin, cause the heap memory to overflow and redirect execution flow to attacker-controlled code. The vulnerability's impact is amplified by the fact that many enterprise environments lack comprehensive application whitelisting controls that might otherwise prevent exploitation of such plugins. Security researchers have documented that this vulnerability can be reliably exploited across multiple operating systems including windows, macos, and linux platforms where Adobe Acrobat Reader is deployed. The lack of input sanitization and memory boundary validation in the plugin component creates a persistent security weakness that can be leveraged for both remote code execution and privilege escalation attacks. This vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the dangers of running outdated software components that contain known security flaws. Organizations should implement immediate mitigations including disabling PDF plugin execution in web browsers, deploying application control policies, and ensuring all users have updated to the latest versions of Adobe Acrobat Reader. The vulnerability also highlights the need for comprehensive security awareness training to prevent users from opening suspicious PDF files that may contain malicious link structures designed to exploit this heap overflow condition.
Organizations should prioritize immediate remediation efforts by updating to the latest versions of Adobe Acrobat Reader that contain patches addressing this heap overflow vulnerability. The patching process should include verification that all affected versions have been properly updated and that no legacy installations remain in the environment. Security teams must implement network monitoring solutions to detect attempts to access or open potentially malicious PDF files that may exploit this vulnerability. Additional mitigations should include configuring web browsers to disable PDF plugin execution, implementing application control policies that restrict Adobe Acrobat Reader access, and deploying endpoint protection solutions that can detect anomalous behavior indicative of exploitation attempts. The vulnerability's impact is further compounded by the fact that many organizations may not have visibility into all instances of Adobe Acrobat Reader installations, particularly in legacy systems or user-owned devices that may not be centrally managed. Security controls should be designed to address both the immediate exploitation threat and the potential for post-exploitation activities that attackers may conduct using the compromised system. Regular vulnerability assessments and penetration testing should include verification of Adobe Acrobat Reader configurations to ensure that the heap overflow vulnerability has been properly addressed. The security community has recognized this vulnerability as particularly dangerous due to its low exploit complexity and high impact potential, making it a priority for immediate remediation across all affected systems. Organizations should also consider implementing zero-trust security models that limit the attack surface by restricting access to PDF processing capabilities and enforcing strict validation of all document content before processing. The vulnerability serves as a reminder of the critical need for maintaining current security postures and the importance of timely patch management in preventing exploitation of known vulnerabilities.