CVE-2015-0032 in Internet Explorer
Summary
by MITRE
vbscript.dll in Microsoft VBScript 5.6 through 5.8, as used with Internet Explorer 8 through 11 and other products, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "VBScript Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 04/12/2022
The vulnerability identified as CVE-2015-0032 represents a critical memory corruption flaw within Microsoft VBScript engine component vbscript.dll affecting versions 5.6 through 5.8. This vulnerability specifically targets Internet Explorer versions 8 through 11 and other Microsoft products that utilize the VBScript runtime environment. The flaw manifests when malicious websites attempt to exploit memory handling mechanisms within the VBScript interpreter, creating a pathway for remote code execution or denial of service conditions. The vulnerability stems from improper memory management during VBScript execution, particularly when processing malformed or crafted script content that triggers buffer overflows or other memory corruption conditions.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read vulnerabilities. The flaw occurs when the vbscript.dll component fails to properly validate input parameters during script execution, allowing attackers to manipulate memory structures through carefully crafted VBScript code embedded in malicious web pages. Attackers can leverage this vulnerability by hosting malicious content that when executed in Internet Explorer triggers the memory corruption, potentially leading to arbitrary code execution with the privileges of the logged-on user. The vulnerability is particularly dangerous because it operates within the browser context, making it accessible through standard web browsing activities without requiring user interaction beyond visiting the malicious site.
From an operational perspective, this vulnerability poses significant risks to enterprise environments where Internet Explorer remains in use, particularly in legacy systems that have not been migrated to modern browsers. The attack surface is extensive given that Internet Explorer was widely deployed across corporate networks and government systems during the affected period. Security analysts have documented successful exploitation attempts where attackers used this vulnerability to establish persistent access to compromised systems, often as part of broader attack campaigns targeting specific organizations. The vulnerability's impact extends beyond immediate execution capabilities to include potential privilege escalation scenarios where attackers could leverage the memory corruption to gain elevated system privileges. Additionally, the vulnerability can be combined with other exploits to create more sophisticated attack chains, making it a valuable target for advanced persistent threat actors.
Mitigation strategies for CVE-2015-0032 include immediate deployment of Microsoft security patches and updates that address the memory corruption in vbscript.dll. Organizations should implement browser hardening measures such as disabling VBScript execution in Internet Explorer through group policy settings or registry modifications. Network-based defenses can include web application firewalls that detect and block known malicious VBScript patterns, though these measures are less reliable than proper patching. Security teams should also consider implementing sandboxing mechanisms for web browsing activities and restricting Internet Explorer's capabilities through enhanced security zones configurations. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how legacy components can remain vulnerable even when operating systems receive regular updates, as the VBScript engine represents a separate component that may not be updated through standard Microsoft update channels. Organizations should also implement continuous monitoring for exploitation attempts and maintain robust incident response procedures to address potential compromise scenarios.