CVE-2018-18356 in Chrome
Summary
by MITRE
An integer overflow in path handling lead to a use after free in Skia in Google Chrome prior to 71.0.3578.80 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/18/2023
The vulnerability identified as CVE-2018-18356 represents a critical integer overflow flaw within the Skia graphics library component that powers Google Chrome's rendering capabilities. This issue specifically manifests in the path handling mechanisms where improper integer arithmetic leads to memory management inconsistencies. The flaw exists in the way Chrome processes graphical paths during HTML page rendering, creating conditions where integer overflow can occur during calculations related to path dimensions or coordinates. When this overflow happens, it results in a use-after-free condition that allows attackers to manipulate memory allocation patterns and potentially corrupt heap structures.
The technical exploitation of this vulnerability occurs through remote code execution via maliciously crafted HTML pages that contain specially constructed graphical elements. The integer overflow in path handling creates a scenario where memory allocated for graphical path data becomes corrupted or improperly managed, leading to a situation where freed memory locations are accessed after their intended use. This use-after-free condition enables attackers to manipulate heap metadata or overwrite critical data structures, potentially allowing for arbitrary code execution with the privileges of the Chrome process. The vulnerability is particularly dangerous because it operates within the browser's rendering engine where legitimate web content processing occurs, making exploitation possible through standard web browsing activities.
From an operational impact perspective, this vulnerability affects Google Chrome versions prior to 71.0.3578.80 and represents a significant risk to users who may encounter malicious web content without realizing it. The attack vector is particularly concerning as it requires no user interaction beyond visiting a compromised website, making it a prime candidate for drive-by download attacks or malicious advertising campaigns. The heap corruption that results from this vulnerability can lead to various security consequences including privilege escalation, information disclosure, or complete system compromise depending on the execution environment and the attacker's objectives. The vulnerability's classification aligns with CWE-190, which addresses integer overflow conditions, and specifically relates to CWE-416, which covers use-after-free conditions.
The mitigation strategy for CVE-2018-18356 centers on updating Google Chrome to version 71.0.3578.80 or later, which includes patches that address the integer overflow in Skia's path handling routines. Organizations should implement comprehensive patch management processes to ensure all Chrome installations are updated promptly. Additionally, network administrators can deploy web application firewalls or content filtering solutions to block suspicious content that might exploit this vulnerability. The mitigation aligns with ATT&CK technique T1059, which covers command and scripting interpreters, as attackers might attempt to leverage this vulnerability to execute malicious payloads through compromised web content. Security teams should also consider implementing browser hardening measures and monitoring for unusual memory allocation patterns that might indicate exploitation attempts.
This vulnerability demonstrates the critical importance of proper integer arithmetic validation in graphics rendering libraries, as even seemingly benign operations like path calculations can lead to severe security consequences. The interaction between the integer overflow and subsequent use-after-free conditions highlights the complex nature of memory corruption vulnerabilities in modern browser engines. The attack surface is particularly wide given that Skia is used across multiple Google products and platforms, making this vulnerability potentially exploitable in various contexts beyond just web browsers. Security researchers have noted that similar issues in graphics libraries often represent persistent challenges due to the complexity of path handling algorithms and the need for high-performance rendering operations that may conflict with security considerations.