CVE-2016-3211 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 9 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Internet Explorer Memory Corruption Vulnerability," a different vulnerability than CVE-2016-0199 and CVE-2016-0200.
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Analysis
by VulDB Data Team • 08/24/2022
This vulnerability affects Microsoft Internet Explorer versions 9 through 11 and represents a critical memory corruption flaw that enables remote code execution or denial of service attacks. The vulnerability stems from improper handling of memory operations within the browser's rendering engine, specifically when processing crafted web content that triggers heap corruption or stack overflow conditions. Attackers can exploit this weakness by hosting malicious web pages that, when loaded in affected IE versions, cause the browser to allocate or access memory in an unsafe manner. The flaw is particularly dangerous because it allows attackers to execute arbitrary code with the privileges of the logged-on user, potentially leading to full system compromise. This vulnerability is distinct from CVE-2016-0199 and CVE-2016-0200, indicating it represents a separate code path or memory handling issue within the browser's architecture. The memory corruption occurs during normal web browsing operations, making it difficult for users to detect or prevent the exploitation. According to CWE classification, this vulnerability maps to CWE-125: Out-of-bounds Read, which describes an attacker reading memory locations outside the intended buffer boundaries, and CWE-787: Out-of-bounds Write, which involves writing to memory locations outside the bounds of a buffer. The attack surface is broad as it affects all versions of Internet Explorer from version 9 through 11, encompassing a significant portion of the browser market during that time period. The vulnerability is particularly concerning in enterprise environments where older IE versions are still in use due to legacy application compatibility requirements.
The operational impact of this vulnerability extends beyond simple code execution to include complete system compromise and potential data exfiltration. When exploited successfully, the memory corruption allows attackers to gain arbitrary code execution privileges, which can be leveraged to install malware, establish backdoors, or perform privilege escalation attacks. The denial of service component of this vulnerability can also be weaponized to disrupt business operations by causing browser crashes or system instability. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.001: Command and Scripting Interpreter - PowerShell, as attackers may use the executed code to establish persistent access or deploy additional malware. The attack chain typically begins with a phishing email or malicious website delivery, followed by user interaction with the crafted content that triggers the memory corruption. The exploitation process requires minimal user interaction beyond visiting the malicious site, making it particularly effective for mass deployment attacks. Security researchers have noted that this vulnerability was actively exploited in the wild during 2016, particularly in targeted attacks against government and corporate entities. The vulnerability's exploitation often involves crafting specific JavaScript or ActiveX content that triggers the memory corruption when processed by the browser's JavaScript engine or HTML parser.
Mitigation strategies for this vulnerability must address both immediate protection and long-term remediation. Microsoft released security patches through Windows Update that addressed the memory corruption issues in affected IE versions, but organizations needed to ensure timely deployment of these updates. The most effective immediate mitigation involves disabling or removing Internet Explorer 9 through 11 from systems where it is not absolutely required for business operations, particularly in environments where other browsers are available. Browser isolation techniques such as using Internet Explorer in a sandboxed environment or employing browser virtualization solutions can provide additional protection layers. Network-level defenses including web application firewalls and content filtering systems can help detect and block malicious web content before it reaches vulnerable browsers. Organizations should implement the principle of least privilege by running Internet Explorer with reduced privileges and limiting user access to system resources. Security monitoring should include detection of unusual memory access patterns or browser crashes that could indicate exploitation attempts. Regular security assessments and penetration testing should be conducted to verify that the mitigation measures are effective and that no other vulnerabilities exist in the browser's codebase. Additionally, user education programs should emphasize the importance of avoiding suspicious websites and email attachments that could deliver malicious content designed to exploit this vulnerability. The remediation process should include comprehensive testing to ensure that security patches do not break existing business applications that depend on older IE functionality. Organizations should also consider migrating to more modern browser architectures that have better memory safety features and more frequent security updates than the older IE versions affected by this vulnerability.