CVE-2018-6031 in Chrome
Summary
by MITRE
Use after free in PDFium in Google Chrome prior to 64.0.3282.119 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2018-6031 represents a critical use-after-free condition within the PDFium component of Google Chrome, affecting versions prior to 64.0.3282.119. This flaw resides in the handling of PDF documents and specifically manifests when processing crafted malicious PDF files that exploit memory management errors during object deallocation. The vulnerability falls under the Common Weakness Enumeration category CWE-416, which specifically addresses the use of freed memory condition. The PDFium library serves as the core PDF rendering engine for Chrome and other Google products, making this issue particularly dangerous as it could be leveraged by remote attackers to execute arbitrary code on affected systems. The flaw occurs when the application frees memory associated with PDF objects but continues to reference those freed memory locations, creating opportunities for heap corruption that can be exploited to gain unauthorized access to system resources.
The operational impact of CVE-2018-6031 extends beyond simple exploitation as it provides attackers with a pathway to achieve remote code execution through carefully crafted PDF documents. When a user opens a malicious PDF file, the PDFium engine processes the document structure and encounters the malformed data that triggers the use-after-free condition. This condition allows attackers to manipulate heap memory layout and potentially overwrite critical data structures or function pointers, enabling them to redirect program execution flow. The vulnerability demonstrates characteristics consistent with the attack pattern described in MITRE ATT&CK technique T1203, which involves the exploitation of memory corruption vulnerabilities to achieve code execution. The remote nature of this attack means that users do not need to perform any special actions beyond opening the malicious document, making it particularly dangerous for enterprise environments where users may encounter such files through email attachments or web browsing.
Mitigation strategies for CVE-2018-6031 primarily focus on immediate software updates and deployment of security patches to address the underlying memory management flaw. Organizations should prioritize updating Google Chrome to version 64.0.3282.119 or later, as this release contains the necessary fixes to prevent the use-after-free condition. Additionally, implementing content filtering measures for PDF files, particularly those received through email or untrusted sources, can provide additional defense-in-depth. Security professionals should consider deploying web application firewalls and sandboxing solutions that can detect and block suspicious PDF content. The vulnerability highlights the importance of proper memory management practices and the need for regular security assessments of third-party libraries used in browser applications. Organizations should also implement monitoring systems to detect potential exploitation attempts and maintain detailed logging of PDF processing activities for forensic analysis purposes. The remediation process should include comprehensive testing of patched versions to ensure that the fix does not introduce compatibility issues with legitimate PDF documents while maintaining the security posture against this specific heap corruption vulnerability.