CVE-2014-1770 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 8 allows remote attackers to execute arbitrary code via crafted JavaScript code that interacts improperly with a CollectGarbage function call on a CMarkup object allocated by the CMarkup::CreateInitialMarkup function.
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Analysis
by VulDB Data Team • 09/12/2025
The CVE-2014-1770 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer 8 that enables remote code execution through malicious JavaScript payloads. This vulnerability specifically targets the browser's JavaScript engine and memory management mechanisms, creating a dangerous condition where freed memory locations are accessed after being deallocated. The flaw occurs when the browser processes crafted JavaScript code that interacts with the CMarkup object lifecycle, particularly during garbage collection operations. The vulnerability stems from improper memory management within the CMarkup::CreateInitialMarkup function, which allocates memory for markup objects that are subsequently freed but still referenced in the garbage collection process.
The technical exploitation of this vulnerability involves crafting malicious JavaScript code that triggers the CMarkup object creation and subsequent garbage collection sequence. When Internet Explorer's JavaScript engine encounters the CollectGarbage function call, it attempts to process a CMarkup object that has already been freed from memory, resulting in a use-after-free condition. This memory corruption allows attackers to manipulate the execution flow and potentially execute arbitrary code with the privileges of the victim user. The vulnerability is particularly dangerous because it leverages the browser's legitimate garbage collection mechanisms to create an exploitable state, making detection and prevention more challenging for security systems.
From an operational perspective, this vulnerability presents significant risks to enterprise environments where Internet Explorer 8 remains in use, as it enables attackers to gain unauthorized code execution capabilities without requiring local system access. The remote nature of the exploit means that attackers can deliver malicious payloads through web-based attacks, making it particularly effective for phishing campaigns and drive-by downloads. The vulnerability's impact extends beyond simple code execution to potentially allow full system compromise, as the executed code can leverage the user's privileges to access sensitive data, install additional malware, or establish persistent access. Organizations running legacy systems that cannot be immediately upgraded face heightened exposure to this type of attack vector.
Security mitigations for CVE-2014-1770 primarily focus on immediate remediation through Microsoft security updates and patches that address the underlying memory management issues. Organizations should implement browser hardening measures including disabling unnecessary JavaScript features, implementing strict content security policies, and deploying web application firewalls to filter malicious payloads. The vulnerability aligns with CWE-416, which describes use-after-free conditions, and maps to ATT&CK technique T1059.007 for JavaScript-based execution. Additionally, security teams should consider implementing user education programs to recognize suspicious web content and maintain up-to-date threat intelligence to detect exploitation attempts. Regular security assessments and vulnerability scanning should include checks for legacy browser usage to identify systems at risk of this and similar memory corruption vulnerabilities.