CVE-2017-15412 in Chrome
Summary
by MITRE
Use after free in libxml2 before 2.9.5, as used in Google Chrome prior to 63.0.3239.84 and other products, allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2017-15412 represents a critical use-after-free condition within the libxml2 library version 2.9.4 and earlier, which was widely integrated into various software applications including Google Chrome before version 63.0.3239.84. This flaw arises from improper memory management during the processing of malformed XML content, creating a scenario where freed memory regions could be accessed by subsequent operations, leading to potential arbitrary code execution. The vulnerability falls under the Common Weakness Enumeration category CWE-416, which specifically addresses use-after-free conditions that occur when a program continues to reference memory after it has been freed, creating opportunities for memory corruption and exploitation.
The technical implementation of this vulnerability involves the libxml2 library's handling of XML parsing operations where a crafted HTML page containing malformed XML structures could trigger a specific code path that results in memory deallocation followed by subsequent access to the same memory region. When Google Chrome processes HTML content that includes embedded XML fragments, the underlying libxml2 parser fails to properly validate memory references during the parsing lifecycle, particularly when dealing with complex nested structures or malformed input that causes the parser to free memory objects while other parts of the codebase still maintain references to them. This creates a race condition where memory corruption occurs at the heap level, potentially allowing attackers to manipulate memory contents to achieve code execution.
The operational impact of this vulnerability extends beyond the immediate browser environment, as libxml2 is integrated into numerous applications and systems that process XML content, including web servers, content management systems, and various enterprise applications. Attackers could leverage this vulnerability through crafted HTML pages delivered via phishing campaigns, malicious websites, or compromised web applications that process user-supplied content. The exploitation requires remote code execution capabilities, making it particularly dangerous in environments where users might encounter malicious content through standard web browsing activities. According to the MITRE ATT&CK framework, this vulnerability maps to techniques involving code injection and privilege escalation through memory corruption, specifically targeting the execution of malicious code in the context of the affected application.
Mitigation strategies for CVE-2017-15412 primarily focus on immediate patching of affected systems and applications, with the most effective solution being the upgrade to libxml2 version 2.9.5 or later, which includes proper memory management fixes and validation checks. Organizations should prioritize updating Google Chrome to version 63.0.3239.84 or higher, as well as ensuring all other applications that utilize libxml2 are updated to versions that contain the memory safety improvements. Additional protective measures include implementing web application firewalls, content filtering systems, and strict input validation for XML content processing. Security teams should also consider deploying intrusion detection systems that monitor for patterns associated with memory corruption exploitation attempts and establish incident response procedures specifically addressing heap corruption vulnerabilities. The remediation process must include comprehensive testing to ensure that patches do not introduce regressions in functionality while maintaining the security improvements that address the underlying use-after-free condition.