CVE-2018-6085 in Chrome
Summary
by MITRE
Re-entry of a destructor in Networking Disk Cache in Google Chrome prior to 66.0.3359.106 allowed a remote attacker to execute arbitrary code via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/12/2023
The vulnerability identified as CVE-2018-6085 represents a critical memory corruption issue within Google Chrome's networking disk cache component that existed prior to version 66.0.3359.106. This flaw manifested as a re-entry condition during destructor execution, creating a scenario where the same destructor function could be called recursively while still processing a previous invocation. The root cause lies in the improper handling of object cleanup sequences within the browser's caching subsystem, specifically when managing network resources stored on disk. Such a condition creates a predictable memory access pattern that can be exploited by malicious actors to manipulate the execution flow of the application.
The technical exploitation of this vulnerability occurs through a carefully crafted HTML page that triggers the problematic code path in Chrome's networking disk cache. When the browser encounters specific network resources that cause the cache to be accessed in a particular sequence, the destructor for cache objects can be re-entered before the previous execution completes. This creates a race condition and memory inconsistency that allows an attacker to manipulate heap memory layout and potentially overwrite critical function pointers or return addresses. The flaw demonstrates characteristics consistent with a classic stack-based buffer overflow scenario, where the re-entry condition provides the attacker with sufficient control over memory operations to redirect program execution.
From an operational perspective, this vulnerability presents a severe risk to end users as it enables remote code execution without requiring any user interaction beyond visiting a malicious website. The attack surface is broad since web browsers are frequently targeted due to their extensive access to system resources and the diverse nature of web content. The exploitability of this flaw is enhanced by the fact that it operates entirely within the browser's memory space, making it difficult to detect through traditional network-based security measures. The vulnerability affects users running affected versions of Chrome and Chromium-based browsers, including various operating systems where these browsers are deployed, potentially compromising the entire system if successful exploitation occurs.
Organizations and individuals should immediately update to Chrome version 66.0.3359.106 or later to remediate this vulnerability. The fix implemented by Google addresses the destructor re-entry issue by ensuring proper state management and preventing recursive calls during object cleanup operations. Security teams should also consider implementing network-based protections such as web application firewalls and content filtering systems to mitigate potential exploitation attempts. Additionally, browser hardening measures including sandboxing, privilege separation, and memory protection mechanisms should be reinforced to limit the impact of any potential exploitation attempts. This vulnerability aligns with CWE-129 and CWE-131 categories related to improper validation of array indices and insufficient control of resource identifiers, and it maps to attack techniques in the ATT&CK framework under T1059 for command and scripting interpreter and T1203 for Exploitation for Client Execution.