CVE-2015-6184 in Internet Explorer
Summary
by MITRE
The CAttrArray object implementation in Microsoft Internet Explorer 7 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (type confusion and memory corruption) via a malformed Cascading Style Sheets (CSS) token sequence in conjunction with modifications to HTML elements, aka "Internet Explorer Memory Corruption Vulnerability," a different vulnerability than CVE-2015-6048 and CVE-2015-6049.
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Analysis
by VulDB Data Team • 07/10/2022
The vulnerability identified as CVE-2015-6184 represents a critical memory corruption flaw within Microsoft Internet Explorer's CAttrArray object implementation that affects versions 7 through 11. This vulnerability operates through a sophisticated type confusion attack that leverages malformed CSS token sequences combined with strategic HTML element modifications to create exploitable conditions in the browser's memory management system. The flaw falls under the broader category of memory corruption vulnerabilities that have historically been among the most dangerous classes of security defects due to their potential for arbitrary code execution.
The technical exploitation mechanism involves the manipulation of CSS parsing logic within Internet Explorer where specifically crafted CSS token sequences interact with HTML element modifications to trigger a type confusion error in the CAttrArray object. This type confusion occurs when the browser's rendering engine incorrectly handles data type expectations during CSS attribute processing, leading to memory corruption that can be leveraged by attackers to execute malicious code. The vulnerability demonstrates characteristics consistent with CWE-122, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and script injection through web browsers. The exploitation requires precise crafting of CSS tokens that, when processed by the browser's CSS parser, cause the CAttrArray object to misinterpret memory locations and data types.
The operational impact of CVE-2015-6184 extends beyond simple denial of service scenarios to include full arbitrary code execution capabilities, making it particularly dangerous for enterprise environments and individual users alike. Attackers can leverage this vulnerability to bypass security controls, escalate privileges, and potentially gain complete system control when users visit malicious websites or interact with compromised web content. The vulnerability's exploitation requires user interaction through web browsing, making it particularly effective in phishing campaigns and drive-by download scenarios where victims are tricked into visiting compromised websites. The memory corruption affects the browser's rendering engine and object management systems, potentially leading to system instability, crashes, or complete system compromise depending on the execution environment and attack vector.
Mitigation strategies for CVE-2015-6184 should prioritize immediate patch deployment through Microsoft's regular security updates, as the vulnerability was addressed in Microsoft Security Bulletin MS15-100. Organizations should implement network-based protections including web application firewalls and content filtering solutions that can detect and block malicious CSS patterns. Browser hardening measures such as disabling unnecessary browser features, implementing strict security policies, and maintaining updated security configurations can reduce the attack surface. Additionally, user education programs should emphasize the importance of avoiding suspicious websites and email attachments that might contain malicious CSS content. Security monitoring should include detection of anomalous CSS parsing patterns and unusual memory allocation behaviors that might indicate exploitation attempts, with particular attention to the memory corruption patterns associated with the CAttrArray object and related CSS processing components.