CVE-2015-2493 in Internet Explorer
Summary
by MITRE
The (1) VBScript and (2) JScript engines in Microsoft Internet Explorer 8 allow remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Scripting Engine Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 06/14/2022
The vulnerability identified as CVE-2015-2493 represents a critical memory corruption flaw affecting the scripting engines of Microsoft Internet Explorer 8. This issue impacts both VBScript and JScript execution environments, creating a significant attack surface for remote code execution and denial of service conditions. The vulnerability arises from improper memory management within the browser's scripting engine components, specifically when processing malformed or crafted web content. Attackers can exploit this weakness by hosting malicious websites that trigger the vulnerable code paths during script execution, potentially leading to complete system compromise. The flaw demonstrates a classic buffer overflow or memory corruption pattern that allows adversaries to manipulate memory addresses and execute arbitrary code with the privileges of the affected user.
This vulnerability maps directly to CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write operations. The technical implementation involves the scripting engines failing to properly validate memory allocations when processing complex script constructs or malformed input data. When Internet Explorer 8 encounters crafted web content containing malicious script code, the vulnerable memory handling routines can be manipulated to overwrite critical memory locations, potentially redirecting program execution flow to attacker-controlled code. The memory corruption occurs during the interpretation and execution phases of the scripting engines, where insufficient bounds checking allows unauthorized memory access patterns. This type of vulnerability is particularly dangerous because it can be triggered through simple web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The operational impact of CVE-2015-2493 extends beyond simple denial of service scenarios to encompass full system compromise capabilities. Attackers can leverage this vulnerability to execute arbitrary code remotely, potentially installing malware, stealing sensitive data, or establishing persistent access to affected systems. The vulnerability affects Windows operating systems running Internet Explorer 8, including Windows Server 2003, Windows Vista, and Windows 7, making it particularly concerning for enterprise environments where legacy browser support remains necessary. Organizations running these older systems face significant risk exposure, as the vulnerability can be exploited through standard web browsing without requiring user interaction or specialized attack vectors. The exploitability factor is high due to the ease with which malicious websites can be constructed to trigger the memory corruption conditions, and the potential for privilege escalation makes this vulnerability particularly attractive to threat actors.
Mitigation strategies for CVE-2015-2493 should focus on immediate patch deployment and operational security measures. Microsoft released security updates addressing this vulnerability through regular security bulletins, and organizations must ensure these patches are applied promptly across all affected systems. Browser isolation techniques and enhanced security configurations can provide additional protection layers, though they do not fully address the underlying memory corruption issue. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter, specifically noting the use of scripting languages for exploitation. Network-based protections such as web application firewalls and content filtering systems can help detect and block malicious script content, while endpoint protection solutions should be configured to monitor for suspicious memory access patterns. Given that Internet Explorer 8 reached end-of-life support, organizations should prioritize migration to modern browser platforms to eliminate exposure to this and similar legacy vulnerabilities. Regular security assessments and vulnerability scanning should include detection of unpatched systems running vulnerable scripting engines to prevent exploitation attempts.