CVE-2017-0223 in Chakra Core
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft Chakra Core in the way JavaScript engines render when handling objects in memory. aka "Scripting Engine Memory Corruption Vulnerability". This vulnerability is unique from CVE-2017-0252.
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Analysis
by VulDB Data Team • 12/06/2022
The vulnerability identified as CVE-2017-0223 represents a critical memory corruption issue within Microsoft Chakra Core JavaScript engine, which serves as the core rendering engine for Internet Explorer and Microsoft Edge browsers. This flaw specifically manifests during the handling of objects in memory, creating a pathway for remote code execution that could be exploited by malicious actors. The vulnerability falls under the broader category of scripting engine flaws that have historically posed significant security risks to web-based applications and browser environments. The Chakra Core engine is responsible for executing JavaScript code in Microsoft's web browsers, making this vulnerability particularly dangerous as it could allow attackers to execute arbitrary code on affected systems without user interaction. The unique nature of this vulnerability distinguishes it from other related issues such as CVE-2017-0252, which indicates that while both vulnerabilities involve the Chakra Core engine, they target different memory handling mechanisms and exploit distinct code paths. This distinction is crucial for security professionals to understand when implementing mitigation strategies and patch management protocols.
The technical implementation of this memory corruption vulnerability stems from improper handling of object references and memory allocation within the JavaScript engine's execution environment. When the Chakra Core engine processes certain JavaScript objects, it fails to properly validate memory boundaries or object references, leading to situations where attacker-controlled data can overwrite critical memory locations. This type of vulnerability typically occurs when the engine does not properly check array bounds or object lifetimes, allowing malicious code to manipulate memory in ways that were not intended by the original software design. The flaw operates at the intersection of memory management and object-oriented programming concepts within the JavaScript engine, where the engine's memory allocator and garbage collector may not adequately protect against malicious input sequences. According to CWE classification, this vulnerability maps to CWE-125: Out-of-bounds Read, which specifically addresses the condition where a program reads data past the end of a valid buffer, potentially leading to memory corruption and arbitrary code execution. The vulnerability's impact is amplified by the fact that it can be triggered through web-based attacks without requiring user interaction, making it particularly dangerous in modern browser environments where users frequently visit untrusted websites.
The operational impact of CVE-2017-0223 extends far beyond simple browser exploitation, as it represents a fundamental weakness in Microsoft's web execution environment that could enable sophisticated attack campaigns. Successful exploitation of this vulnerability could allow attackers to execute arbitrary code with the privileges of the affected user, potentially leading to complete system compromise, data exfiltration, or the installation of persistent backdoors. The vulnerability's remote execution capability means that attackers could deliver malicious JavaScript code through compromised websites, email attachments, or other web-based delivery mechanisms, making it particularly attractive for large-scale attack operations. Security researchers have noted that this vulnerability is particularly concerning because it can be exploited in zero-day attack scenarios, where defenders have no prior knowledge of the flaw and therefore cannot implement preventive measures. The vulnerability's presence in both Internet Explorer and Microsoft Edge browsers creates a broad attack surface, as these browsers represent significant portions of the enterprise and consumer web browsing environments. The attack vector typically involves crafting malicious JavaScript code that, when executed by the vulnerable Chakra Core engine, triggers the memory corruption condition and allows for code execution. This vulnerability has been classified under the MITRE ATT&CK framework as part of the T1059.007 technique, which involves the use of scripting languages for execution, specifically targeting the Windows Command Shell and PowerShell environments that are commonly used by attackers for post-exploitation activities.
Mitigation strategies for CVE-2017-0223 require immediate attention from system administrators and security teams, as the vulnerability poses an elevated risk to organizations that have not yet applied patches. Microsoft has released security updates that address this vulnerability through patches to the Chakra Core engine, and organizations should prioritize deployment of these patches across all affected systems. The recommended approach involves implementing a layered security strategy that includes browser hardening, network segmentation, and regular patch management procedures to prevent exploitation attempts. Security professionals should also consider implementing web application firewalls and content filtering solutions that can detect and block malicious JavaScript patterns associated with this vulnerability. Additionally, organizations should conduct vulnerability assessments to identify systems running vulnerable versions of Internet Explorer or Microsoft Edge, as these browsers are most susceptible to exploitation. The mitigation process should also include user education regarding safe browsing practices and the importance of keeping software updated. Organizations should monitor exploit indicators and threat intelligence feeds to identify potential attack attempts targeting this vulnerability, as the exploitation techniques often follow established patterns that can be detected through network monitoring and endpoint detection systems. Regular security audits and penetration testing should be conducted to validate the effectiveness of implemented controls and ensure that the vulnerability has been properly addressed across all affected environments.