CVE-2015-6059 in Internet Explorer
Summary
by MITRE
The Microsoft (1) VBScript 5.7 and 5.8 and (2) JScript 5.7 and 5.8 engines, as used in Internet Explorer 8 through 11 and other products, allow remote attackers to obtain sensitive information from process memory via a crafted web site, aka "Scripting Engine Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 06/21/2022
The CVE-2015-6059 vulnerability represents a critical information disclosure flaw affecting Microsoft's scripting engines used in Internet Explorer and other applications. This vulnerability specifically targets VBScript 5.7 and 5.8 as well as JScript 5.7 and 5.8 engines, creating a significant security risk for users of Internet Explorer versions 8 through 11. The flaw enables remote attackers to extract sensitive data from process memory through maliciously crafted web pages, potentially exposing confidential information that should remain protected within application processes.
The technical mechanism behind this vulnerability involves improper memory handling within the scripting engines that process JavaScript and VBScript code. When these engines encounter malformed or specially crafted script content, they fail to properly validate memory access operations, allowing unauthorized data retrieval from adjacent memory locations. This type of vulnerability falls under the CWE-200 category of "Information Exposure" and specifically relates to CWE-125 "Out-of-bounds Read" conditions where the scripting engine reads memory beyond its intended boundaries. The vulnerability operates at the intersection of memory management and script execution, creating a pathway for attackers to harvest sensitive information that may include session tokens, user credentials, or other confidential data stored in memory.
The operational impact of CVE-2015-6059 extends beyond simple information disclosure, as the extracted memory contents could contain critical system information that attackers might leverage for further exploitation. This vulnerability enables attackers to gather process-specific data that could aid in crafting more sophisticated attacks, including buffer overflow exploits, privilege escalation attempts, or targeted attacks against other system components. The affected Internet Explorer versions 8 through 11 represent a wide range of legacy browsers that were still in use, making this vulnerability particularly dangerous as it could affect organizations with older systems or those slow to update their browser infrastructure. The attack vector requires only a user to visit a malicious website, making it highly exploitable in phishing campaigns or compromised legitimate websites.
Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.007 for "Scripting - JavaScript" and T1068 for "Exploitation for Privilege Escalation," as the initial information disclosure can serve as a stepping stone for more advanced attacks. Organizations must implement multiple layers of defense including browser security updates, network-based protections, and user education to mitigate this risk. The vulnerability demonstrates the importance of proper memory management in scripting engines and highlights why regular security updates are essential for maintaining secure computing environments. Microsoft addressed this vulnerability through security updates that improved memory validation in the scripting engines, but the widespread use of affected Internet Explorer versions meant that many systems remained at risk until comprehensive patching was completed.