CVE-2019-5867 in Chrome
Summary
by MITRE
Out of bounds read in JavaScript in Google Chrome prior to 76.0.3809.100 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 07/23/2020
The vulnerability identified as CVE-2019-5867 represents a critical out-of-bounds read flaw within the JavaScript engine of Google Chrome browser versions prior to 76.0.3809.100. This issue stems from improper memory management during JavaScript execution, specifically when processing crafted HTML content that triggers memory access violations. The flaw manifests as a heap corruption condition that can be exploited by remote attackers through malicious web pages, making it particularly dangerous in the context of modern web browsing where users frequently encounter untrusted content. The vulnerability operates at the intersection of memory safety and browser security, where the JavaScript engine fails to properly validate array bounds during memory operations, leading to unauthorized memory access patterns that can be manipulated for exploitation purposes.
The technical implementation of this vulnerability involves the JavaScript engine's handling of memory allocation and access patterns when processing specific HTML constructs. When a malicious page loads with crafted JavaScript code, the engine attempts to read memory locations beyond the allocated buffer boundaries, creating a condition where adjacent memory segments can be accessed or modified. This out-of-bounds read can potentially expose sensitive information from memory or corrupt heap structures, providing attackers with opportunities to escalate privileges or execute arbitrary code. The flaw falls under the CWE-125 Out-of-bounds Read classification, which specifically addresses memory access violations that occur when programs read data beyond the boundaries of allocated memory regions. The vulnerability demonstrates how seemingly benign HTML processing can lead to serious security implications when underlying memory management mechanisms fail to properly validate access boundaries.
The operational impact of CVE-2019-5867 extends beyond simple information disclosure, as the heap corruption vulnerability creates a pathway for more sophisticated attacks within the browser environment. Remote attackers can leverage this vulnerability to potentially execute code within the context of the browser process, bypassing standard security boundaries that typically protect against such exploits. The attack vector requires only a user to visit a malicious webpage, making it particularly dangerous in phishing campaigns or compromised websites where users might inadvertently trigger the exploit. This vulnerability aligns with ATT&CK technique T1059.007 for JavaScript execution and T1068 for local privilege escalation, as the initial compromise can lead to broader system access. The risk is amplified by the fact that the vulnerability affects all versions of Chrome prior to 76.0.3809.100, representing a substantial user base that would be vulnerable to exploitation.
Mitigation strategies for CVE-2019-5867 primarily focus on immediate patching and browser updates to the affected versions. Users should upgrade to Chrome version 76.0.3809.100 or later where the vulnerability has been addressed through improved memory validation and bounds checking mechanisms. Organizations should implement browser hardening measures including disabling unnecessary JavaScript features, employing content security policies, and maintaining updated threat intelligence feeds to identify and block malicious web content. The fix typically involves enhancing the JavaScript engine's memory management routines to properly validate array indices and buffer boundaries before memory access operations. Security teams should also consider implementing web application firewalls and network-based intrusion detection systems to monitor for exploitation attempts targeting this vulnerability, as the attack surface includes not only direct user interaction but also potential cross-site scripting scenarios where the vulnerability could be leveraged through compromised web applications.