CVE-2020-1073 in Edge
Summary
by MITRE
A remote code execution vulnerability exists in the way that the ChakraCore scripting engine handles objects in memory, aka 'Scripting Engine Memory Corruption Vulnerability'.
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Analysis
by VulDB Data Team • 10/23/2020
The vulnerability identified as CVE-2020-1073 represents a critical remote code execution flaw within Microsoft's ChakraCore JavaScript engine, which serves as the core scripting engine for Internet Explorer and Microsoft Edge browsers. This vulnerability stems from improper handling of objects in memory, creating a pathway for attackers to execute arbitrary code on affected systems. The ChakraCore engine is widely deployed across Microsoft's browser ecosystem and various applications that rely on JavaScript execution, making this vulnerability particularly concerning from a security perspective. The flaw exists in the memory management routines where objects are allocated, manipulated, and deallocated within the engine's runtime environment, creating opportunities for memory corruption that can be exploited by malicious actors.
The technical nature of this vulnerability manifests as a memory corruption issue that occurs during the normal operation of the ChakraCore engine when processing specific JavaScript objects. Attackers can craft malicious JavaScript code that, when executed, causes the engine to improperly handle memory references, leading to buffer overflows, use-after-free conditions, or other memory corruption scenarios. This type of vulnerability falls under the CWE-125 vulnerability class, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common precursors to remote code execution exploits. The vulnerability's exploitation typically involves manipulating object references in ways that cause the engine to write data beyond allocated memory boundaries, potentially allowing attackers to overwrite critical memory structures or inject malicious code into the process space.
From an operational standpoint, the impact of CVE-2020-1073 is severe as it enables attackers to achieve full remote code execution capabilities on systems running affected versions of Internet Explorer or Microsoft Edge. This vulnerability can be exploited through various attack vectors including malicious websites, phishing emails containing compromised web content, or even through compromised web applications that utilize the ChakraCore engine. The attack surface extends beyond just web browsers to any application that incorporates ChakraCore as its scripting engine, including various Microsoft products and third-party applications that leverage Microsoft's JavaScript runtime. The vulnerability's remote nature means that exploitation does not require local system access, making it particularly dangerous for enterprise environments where users may inadvertently visit malicious sites or receive compromised email attachments.
The exploitation of this vulnerability aligns with tactics described in the MITRE ATT&CK framework under the T1059.007 technique for 'Command and Scripting Interpreter: JavaScript' and T1203 for 'Exploitation for Client Execution'. Security professionals should note that the vulnerability can be chained with other exploits to create more sophisticated attack scenarios, potentially leading to privilege escalation or lateral movement within compromised networks. Organizations should implement immediate mitigations including applying Microsoft's security patches, implementing browser hardening measures, and deploying network-based protections such as web application firewalls. Additionally, the vulnerability highlights the importance of keeping all scripting engines and runtime environments updated, as the complexity of modern JavaScript engines creates numerous potential attack surfaces. The vulnerability also underscores the need for comprehensive memory safety testing and the implementation of exploit mitigation techniques such as address space layout randomization and data execution prevention to reduce the effectiveness of potential exploitation attempts.