CVE-2017-15408 in Chrome
Summary
by MITRE
Heap buffer overflow in Omnibox in Google Chrome prior to 63.0.3239.84 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file that is mishandled by PDFium.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/04/2023
The heap buffer overflow vulnerability identified as CVE-2017-15408 represents a critical security flaw within Google Chrome's Omnibox component that existed prior to version 63.0.3239.84. This vulnerability specifically manifests when Chrome processes PDF files through the PDFium library, creating a pathway for remote attackers to exploit heap corruption through carefully crafted malicious PDF documents. The flaw resides in how the Omnibox handles certain PDF file structures, particularly those that trigger improper memory management during PDF rendering operations. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, where insufficient bounds checking allows attackers to write beyond allocated memory boundaries, potentially leading to arbitrary code execution or system compromise. This type of vulnerability is particularly dangerous because it can be triggered through web-based attacks without requiring user interaction beyond visiting a malicious website or opening a compromised PDF document.
The technical implementation of this vulnerability involves the PDFium library's handling of malformed PDF objects within the Omnibox context, where memory allocation occurs based on parsed PDF data without adequate validation of buffer boundaries. When Chrome processes a specially crafted PDF file, the PDFium component attempts to allocate heap memory for rendering or parsing operations, but fails to properly validate input parameters, resulting in a buffer overflow condition. This condition allows an attacker to overwrite adjacent memory locations within the heap, potentially corrupting critical data structures or executing malicious code within the Chrome process context. The exploitation mechanism leverages the fact that PDF processing occurs within the browser's memory space, making it possible for attackers to manipulate heap metadata and achieve code execution through carefully constructed input data that bypasses normal security mitigations.
The operational impact of CVE-2017-15408 extends beyond simple heap corruption, as it provides attackers with a potential foothold for more sophisticated attacks within the browser environment. The vulnerability can be exploited through various attack vectors including phishing campaigns, malicious websites, or compromised PDF documents distributed through social engineering. The remote nature of the exploit means that users do not need to interact with the malicious content directly, as simply viewing a compromised PDF in Chrome can trigger the vulnerability. This makes the attack surface particularly broad and difficult to defend against through traditional user education methods alone. The vulnerability's classification under ATT&CK technique T1203 (Exploitation for Client Execution) demonstrates its potential for lateral movement within compromised systems, as successful exploitation can provide attackers with a persistent execution environment within the browser's memory space.
Mitigation strategies for CVE-2017-15408 primarily focus on immediate patching of affected Chrome versions, as the vulnerability was addressed through updates that implemented proper bounds checking in the PDFium library's memory management routines. Organizations should prioritize updating to Chrome version 63.0.3239.84 or later, which includes fixes that prevent the heap buffer overflow condition during PDF processing. Additionally, implementing web application firewalls and content filtering solutions can provide additional layers of protection by blocking suspicious PDF content before it reaches user browsers. Security teams should also consider deploying sandboxing mechanisms and privilege separation techniques to limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of regular security updates and the need for organizations to maintain comprehensive patch management programs, as the flaw existed for several months before being addressed through official Chrome releases. Organizations should also implement monitoring solutions to detect unusual PDF processing activities that might indicate exploitation attempts, and maintain up-to-date threat intelligence feeds to identify known malicious PDF samples associated with this vulnerability.