CVE-2017-16361 in Acrobat Reader
Summary
by MITRE
An issue was discovered in Adobe Acrobat and Reader: 2017.012.20098 and earlier versions, 2017.011.30066 and earlier versions, 2015.006.30355 and earlier versions, and 11.0.22 and earlier versions. This vulnerability is an instance of a security bypass vulnerability when handling XFDF files.
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Analysis
by VulDB Data Team • 09/04/2024
This vulnerability exists in Adobe Acrobat and Reader software versions prior to the specified patches, representing a security bypass flaw that specifically affects the handling of XML Forms Data Format files. The issue manifests when the software processes XFDF files, which are used for exchanging form data between different PDF applications and web browsers. The vulnerability allows an attacker to bypass intended security controls during the processing of these files, potentially enabling unauthorized access or execution of malicious code. This type of vulnerability falls under the broader category of improper input validation, where the software fails to properly validate or sanitize the input data before processing it. The security bypass occurs at the file parsing level where the application does not adequately verify the structure and content of XFDF files, creating an opportunity for attackers to craft malicious payloads that can exploit the software's processing logic. The vulnerability is particularly concerning because XFDF files are commonly used in web-based PDF forms and document workflows, making them a frequent attack vector for malicious actors targeting Adobe Acrobat and Reader users.
The technical flaw stems from insufficient validation of XFDF file structures and content within the Adobe software's form processing engine. When the application encounters an XFDF file, it fails to properly validate the XML structure and embedded data, allowing potentially malicious content to be processed without adequate security checks. This processing error creates a path where an attacker can manipulate the XFDF file to bypass normal security mechanisms that would typically prevent execution of malicious code or unauthorized access to system resources. The vulnerability is classified as a security bypass because it allows an attacker to circumvent controls that should normally prevent dangerous operations from occurring during file processing. This flaw enables attackers to potentially execute arbitrary code, access sensitive information, or perform other malicious actions that would not normally be permitted when processing legitimate XFDF files. The issue demonstrates a classic weakness in input validation and proper security boundary enforcement within the software's file handling routines.
The operational impact of this vulnerability extends beyond simple exploitation as it affects a widely used software platform with extensive deployment across enterprise environments and individual users. Organizations relying on Adobe Acrobat and Reader for document processing and form handling are potentially at risk of unauthorized access, data breaches, or system compromise when processing XFDF files. The vulnerability's presence in multiple version ranges indicates a prolonged period during which users remained exposed to potential exploitation, increasing the attack surface and potential damage. Attackers could leverage this vulnerability to target specific organizations by sending malicious XFDF files through email or other delivery mechanisms, potentially leading to successful compromise of systems where Adobe Reader is installed. The security bypass nature means that traditional security measures such as antivirus scanning or network monitoring may not detect the malicious activity, as the exploit occurs within the legitimate software processing chain. This vulnerability particularly impacts environments where users frequently interact with web forms, electronic document workflows, or collaborative document editing systems that utilize XFDF files.
Mitigation strategies for this vulnerability should focus on immediate software updates and deployment of the latest patches provided by Adobe to address the specific security bypass issue. Organizations should implement comprehensive patch management procedures to ensure all instances of Adobe Acrobat and Reader are updated promptly, particularly given the multiple affected version ranges. Network segmentation and access controls should be enhanced to limit exposure of systems that process XFDF files, while security monitoring should be configured to detect unusual file processing activities. Security awareness training should be conducted to educate users about the risks of opening untrusted XFDF files and the importance of verifying file sources before processing. Additional defensive measures include implementing sandboxing for PDF processing, deploying application whitelisting policies, and configuring email security appliances to filter potentially malicious XFDF attachments. The vulnerability aligns with CWE-20, Improper Input Validation, and represents a typical example of how insecure file processing can lead to security bypass scenarios. From an ATT&CK perspective, this vulnerability maps to techniques involving execution through file processing and privilege escalation through application exploitation, making it a significant concern for enterprise security teams implementing comprehensive threat defense strategies.