CVE-2012-1539 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 9 allows remote attackers to execute arbitrary code via a crafted web site, aka "CTreePos Use After Free Vulnerability."
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Analysis
by VulDB Data Team • 10/22/2024
The CVE-2012-1539 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer 9 that enables remote code execution through malicious web content. This vulnerability specifically affects the CTreePos class within the browser's rendering engine, creating a scenario where freed memory locations are accessed after being deallocated, leading to potential exploitation by attackers. The flaw exists in the way Internet Explorer handles certain DOM (Document Object Model) operations, particularly when processing tree structures in web pages. This type of vulnerability is particularly dangerous because it can be triggered remotely through web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The technical implementation of this vulnerability stems from improper memory management within Internet Explorer 9's JavaScript engine and DOM handling components. When processing certain web page elements, the browser allocates memory for CTreePos objects and subsequently frees them, but fails to properly invalidate references to these objects. Attackers can craft malicious web pages that trigger specific sequences of DOM operations, causing the browser to access already freed memory locations. This memory access pattern creates a predictable exploitation scenario where attackers can manipulate the freed memory to inject and execute arbitrary code with the privileges of the victim user. The vulnerability falls under CWE-416, which specifically addresses use-after-free conditions in software implementations.
From an operational perspective, this vulnerability poses significant risk to enterprise environments where users regularly browse the internet and access potentially untrusted websites. The remote exploitation capability means that attackers can compromise systems simply by having users visit malicious websites, making it particularly dangerous for organizations with limited security awareness training. The exploit can be delivered through various vectors including phishing campaigns, compromised websites, or malicious advertisements, allowing attackers to gain full system control without requiring user interaction beyond normal web browsing. The vulnerability affects all versions of Internet Explorer 9 and can be leveraged to establish persistent access, escalate privileges, and potentially spread to other systems within the network. This makes it a prime target for advanced persistent threat actors and cybercriminals seeking to establish footholds in enterprise environments.
The mitigation strategies for CVE-2012-1539 primarily focus on immediate patching and browser security hardening measures. Microsoft released security updates that addressed the memory management issues in Internet Explorer 9, requiring organizations to apply these patches promptly to prevent exploitation. Additionally, implementing browser security features such as Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP), and Enhanced Protected Mode can significantly reduce exploit success rates. Network-based protections including web proxies with content filtering, firewall rules blocking suspicious traffic, and intrusion detection systems can provide additional layers of defense. Organizations should also consider implementing browser isolation techniques and encouraging users to adopt secure browsing practices such as avoiding untrusted websites and keeping browsers updated. The vulnerability demonstrates the importance of regular security assessments and maintaining up-to-date security patches as part of comprehensive cybersecurity programs. This type of vulnerability is frequently referenced in ATT&CK framework under the T1059 technique for command and control communications, and T1068 for exploit for privilege escalation, highlighting its role in broader attack chains and the need for multi-layered defensive strategies.