CVE-2019-5787 in Chrome
Summary
by MITRE
Use-after-garbage-collection in Blink in Google Chrome prior to 73.0.3683.75 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/15/2020
The vulnerability CVE-2019-5787 represents a critical use-after-garbage-collection issue within the Blink rendering engine that powers Google Chrome browsers. This flaw exists in versions prior to 73.0.3683.75 and demonstrates a classic memory safety vulnerability that can be exploited remotely. The vulnerability stems from improper handling of object lifecycles in the JavaScript engine's garbage collection process, where objects are accessed after they have been deallocated from memory. Such memory corruption issues are particularly dangerous because they can lead to arbitrary code execution, making them highly attractive targets for malicious actors seeking to compromise user systems. The vulnerability is classified under CWE-416, which specifically addresses use-after-free conditions, and aligns with ATT&CK technique T1059.007 for script-based exploitation.
The technical implementation of this vulnerability occurs when Chrome processes crafted HTML pages that trigger specific JavaScript operations leading to premature garbage collection of objects while still in use. When the garbage collector reclaims memory space occupied by these objects, subsequent access attempts to the freed memory locations result in heap corruption. This corruption can be leveraged by attackers to overwrite critical memory structures or inject malicious code into the browser process. The exploitation typically involves creating specific memory allocation patterns that, when processed by Blink's JavaScript engine, cause objects to be freed prematurely while references to them persist. The vulnerability is particularly concerning because it operates at the browser's core rendering layer, allowing attackers to potentially execute code with the privileges of the compromised browser process.
The operational impact of CVE-2019-5787 extends beyond simple browser compromise, as successful exploitation can lead to complete system compromise through various attack vectors. Attackers can leverage this vulnerability to execute malicious code on victim machines, potentially installing malware, stealing sensitive data, or establishing persistent backdoors. The remote nature of the exploit means that victims need only visit a malicious webpage to be compromised, making this vulnerability particularly dangerous for widespread deployment. Organizations using affected Chrome versions face significant risk exposure, as the vulnerability can be exploited through standard web browsing activities without requiring any special user interaction beyond visiting compromised sites. This makes the vulnerability particularly effective for drive-by attack scenarios and mass exploitation campaigns.
Mitigation strategies for CVE-2019-5787 primarily focus on immediate browser updates to versions 73.0.3683.75 or later where the vulnerability has been patched. Organizations should implement comprehensive patch management procedures to ensure all Chrome installations are updated promptly. Additional protective measures include deploying web application firewalls, implementing strict content security policies, and utilizing sandboxing technologies that limit the potential impact of successful exploits. Security teams should also consider implementing browser hardening configurations that disable unnecessary JavaScript features and restrict memory management operations. Network-level protections such as DNS filtering and web content filtering can provide additional defense-in-depth layers. Organizations should monitor for exploitation attempts through security information and event management systems, as indicators of compromise often manifest as unusual network traffic patterns or memory access violations. Regular security assessments and penetration testing help identify potential exploitation vectors and ensure that mitigation measures remain effective against evolving attack techniques.