CVE-2018-17481 in Chrome
Summary
by MITRE
Incorrect object lifecycle in PDFium in Google Chrome prior to 71.0.3578.80 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file.
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Analysis
by VulDB Data Team • 06/18/2023
CVE-2018-17481 represents a critical heap corruption vulnerability within PDFium, the PDF rendering library used by Google Chrome and numerous other applications. This vulnerability stems from improper object lifecycle management during PDF document processing, specifically when handling crafted malicious PDF files. The flaw exists in how PDFium manages memory allocation and deallocation for objects within the document parsing process, creating opportunities for attackers to manipulate memory structures through carefully constructed PDF content. The vulnerability is classified under CWE-415 as double free or memory corruption due to improper object lifecycle handling, which directly impacts the integrity of memory management operations.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious PDF file that triggers improper memory cleanup during document rendering. When Chrome processes such a file, the PDFium library fails to properly manage object references, leading to heap corruption that can result in arbitrary code execution. The vulnerability manifests during the parsing and rendering phases of PDF documents, particularly when handling complex object structures, cross-reference tables, or embedded JavaScript elements within the PDF file. Attackers can leverage this flaw to overwrite memory locations, potentially executing malicious code with the privileges of the Chrome process, which typically runs with limited user privileges but can still compromise system security.
The operational impact of CVE-2018-17481 extends beyond individual browser exploitation to encompass broader security implications for web-based document processing environments. This vulnerability affects not only end-user browsers but also any application that relies on PDFium for PDF rendering capabilities, including enterprise document management systems, email clients, and PDF viewers. The remote exploitation capability means that users can be compromised simply by viewing a malicious PDF file, making this a particularly dangerous vulnerability for phishing campaigns and drive-by download attacks. The vulnerability's presence in Chrome versions prior to 71.0.3578.80 created a significant attack surface for threat actors targeting organizations with outdated browser installations.
Mitigation strategies for CVE-2018-17481 primarily focus on immediate software updates and deployment of security patches. Organizations should prioritize updating Chrome to version 71.0.3578.80 or later, where the vulnerability has been addressed through improved object lifecycle management in PDFium. Additionally, implementing network-based security controls such as web application firewalls and PDF content filtering can provide additional layers of protection. Security teams should also consider deploying sandboxing mechanisms and privilege separation techniques to limit the potential impact of successful exploitation attempts. The vulnerability's classification under ATT&CK technique T1203 (Exploitation for Client Execution) emphasizes the need for comprehensive endpoint protection strategies that include regular security assessments and monitoring for suspicious PDF-related activities. Organizations should also implement security awareness training to educate users about the risks of opening untrusted PDF files and the importance of keeping software updated to prevent exploitation of known vulnerabilities.