CVE-2017-5057 in Chrome
Summary
by MITRE
Type confusion in PDFium in Google Chrome prior to 58.0.3029.81 for Mac, Windows, and Linux, and 58.0.3029.83 for Android, allowed a remote attacker to perform an out of bounds memory read via a crafted PDF file.
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Analysis
by VulDB Data Team • 09/17/2020
CVE-2017-5057 represents a critical type confusion vulnerability within the PDFium library that powers Google Chrome's PDF rendering capabilities across multiple operating systems. This vulnerability stems from improper handling of data types during PDF processing, specifically when the PDFium component attempts to interpret and manipulate object structures within maliciously crafted PDF files. The flaw manifests as a type confusion error where the software incorrectly treats one data type as another, leading to unpredictable behavior and memory access violations. The vulnerability is particularly dangerous because it can be exploited remotely through web-based PDF content, requiring no user interaction beyond visiting a malicious website or opening a compromised PDF document.
The technical implementation of this vulnerability involves the PDFium library's object handling mechanisms failing to properly validate type information during parsing operations. When processing malformed PDF objects, the library executes a type confusion attack that allows an attacker to manipulate memory pointers and access regions beyond the intended data boundaries. This out-of-bounds memory read occurs because the PDFium parser does not adequately verify the expected data type before performing operations that assume a specific memory layout. The vulnerability specifically affects Chrome versions prior to 58.0.3029.81 on macOS, Windows, and Linux platforms, as well as Android versions prior to 58.0.3029.83, indicating a widespread impact across the Chrome ecosystem. According to CWE-466, this vulnerability maps directly to the weakness of improper handling of type confusion, which is classified as a high-severity issue in the Common Weakness Enumeration framework.
The operational impact of CVE-2017-5057 extends beyond simple information disclosure, as remote attackers can leverage this vulnerability to execute arbitrary code within the context of the Chrome browser. This type of vulnerability enables attackers to potentially escalate privileges, access sensitive user data, or establish persistent footholds within affected systems. The remote exploitability means that users can be compromised simply by visiting malicious websites or opening infected PDF documents, making this vulnerability particularly attractive to threat actors conducting large-scale campaigns. The memory read operations can potentially expose sensitive information from adjacent memory regions, including browser session data, user credentials, or other confidential information stored in memory. This vulnerability aligns with ATT&CK technique T1059.007 for remote code execution and T1068 for privilege escalation through browser-based attacks.
Mitigation strategies for CVE-2017-5057 primarily focus on immediate software updates and browser security hardening measures. Organizations should prioritize updating all Chrome installations to versions 58.0.3029.81 or later, ensuring that both desktop and mobile platforms receive the necessary security patches. Additionally, implementing browser security policies such as sandboxing, content security policies, and restricted PDF handling can significantly reduce the attack surface. Network-level protections including web application firewalls and PDF content filtering can provide additional defense-in-depth measures. Security teams should also consider deploying endpoint detection and response solutions that can monitor for suspicious PDF processing activities and anomalous memory access patterns. The vulnerability serves as a reminder of the critical importance of keeping browser components updated and maintaining robust security hygiene practices across enterprise environments.