CVE-2017-3118 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 a security bypass vulnerability related to execution of malicious attachments.
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Analysis
by VulDB Data Team • 01/08/2021
Adobe Acrobat Reader contains a security bypass vulnerability that allows attackers to execute malicious code through crafted attachments without proper authentication or authorization. This vulnerability affects multiple versions of Adobe Acrobat Reader across different release cycles, including the 2017, 2015, and 11.0.x series, making it a widespread concern for organizations relying on these software versions. The flaw stems from insufficient validation mechanisms that permit unauthorized execution of potentially harmful content when users open maliciously crafted PDF files or attachments. The vulnerability specifically relates to how the application handles file execution contexts and does not properly enforce security boundaries between legitimate and malicious content. This weakness creates a pathway for attackers to bypass standard security controls and execute arbitrary code on affected systems. The security bypass occurs during the processing of PDF attachments where the application fails to adequately verify the integrity and authenticity of loaded content. This vulnerability aligns with CWE-119 which addresses improper restriction of operations within a limited context and CWE-250 which covers execution of unknown software. The operational impact of this vulnerability is significant as it allows for remote code execution without user interaction beyond opening a malicious attachment, making it particularly dangerous in phishing campaigns and targeted attacks. Attackers can leverage this vulnerability to install malware, steal sensitive data, or establish persistent access to compromised systems. The vulnerability also maps to ATT&CK technique T1204.002 which involves user execution of malicious files, specifically targeting the execution of malicious attachments. Organizations using affected versions of Adobe Acrobat Reader are at risk of sophisticated attacks that can bypass traditional security measures such as antivirus solutions and email filtering systems. The vulnerability demonstrates a critical flaw in the application's security architecture where the trust model is insufficiently enforced during file processing operations. The security bypass allows attackers to circumvent the application's built-in protections and execute malicious payloads with the privileges of the user running the application.
The technical implementation of this vulnerability involves improper handling of file execution contexts within the PDF processing engine. When a user opens a maliciously crafted PDF attachment, the application fails to properly validate the file structure and embedded content before executing any code contained within the document. This validation failure occurs at multiple levels including file format parsing, content interpretation, and execution context management. The vulnerability is particularly concerning because it can be exploited through simple email attachments or web downloads without requiring any special privileges or advanced exploitation techniques. Attackers can craft PDF files that appear legitimate but contain hidden malicious code that executes when the document is opened. The security bypass is not limited to specific file types or execution environments, making it applicable across various attack scenarios. The vulnerability affects both desktop and mobile versions of the affected software, extending the attack surface significantly. Organizations should consider the broader implications of this vulnerability when assessing their overall security posture, as it represents a fundamental flaw in the application's security architecture. The vulnerability's persistence across multiple software versions indicates a systemic issue in how Adobe implemented security controls within their PDF processing capabilities. The exploitation of this vulnerability can lead to complete system compromise, data exfiltration, and persistent backdoor access to affected systems. Security researchers have identified that the vulnerability is particularly dangerous in enterprise environments where users frequently open email attachments from external sources. The attack vector is straightforward and does not require specialized knowledge or tools beyond basic PDF crafting capabilities, making it accessible to a wide range of threat actors.
Mitigation strategies for this vulnerability should include immediate patching of all affected Adobe Acrobat Reader installations to the latest available versions. Organizations must implement comprehensive software update policies that ensure all systems receive security patches promptly. The vulnerability can be partially mitigated through email filtering solutions that scan for malicious PDF attachments and prevent their delivery to end users. Network segmentation and application whitelisting can help limit the potential impact of successful exploitation attempts. Security awareness training for users should emphasize the importance of verifying the authenticity of email attachments before opening them. System administrators should monitor for unusual file execution patterns and implement behavioral analysis tools to detect potential exploitation attempts. The vulnerability also requires consideration of endpoint protection solutions that can detect and block malicious PDF content during processing. Regular security assessments should include testing for the presence of vulnerable software versions and verification of proper patch deployment. Organizations should also consider implementing additional security controls such as sandboxing environments for PDF processing and restricting user privileges when opening potentially malicious files. The implementation of these mitigations should follow established security frameworks and best practices to ensure comprehensive protection against this and similar vulnerabilities. The vulnerability serves as a reminder of the critical importance of maintaining current software versions and implementing layered security approaches to protect against sophisticated threats. Regular vulnerability assessments and penetration testing should be conducted to identify and remediate similar security gaps in other software applications within the organization's infrastructure.