CVE-2015-6135 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 • 06/29/2022
This vulnerability affects the scripting engines used in Microsoft Internet Explorer versions 8 through 11, specifically targeting VBScript 5.7 and 5.8 as well as JScript 5.7 and 5.8 implementations. The flaw represents a critical information disclosure issue that enables remote attackers to extract sensitive data from process memory through maliciously crafted web content. The vulnerability stems from improper handling of memory operations within the scripting engines, creating potential exposure of confidential information that could be leveraged for further attacks.
The technical implementation of this vulnerability involves memory corruption patterns within the scripting engine's memory management systems. When processing crafted web content, the engines fail to properly validate or sanitize memory access operations, allowing attackers to manipulate memory pointers and read data from adjacent memory locations. This type of vulnerability aligns with CWE-200, which specifically addresses information exposure through improper error handling or memory access patterns. The flaw manifests when the scripting engines encounter malformed input that triggers unexpected memory access sequences, potentially exposing stack contents, heap data, or other sensitive process information.
The operational impact of CVE-2015-6135 extends beyond simple information disclosure, as the leaked memory contents could contain sensitive data such as encryption keys, session tokens, user credentials, or application-specific variables. Attackers could potentially reconstruct parts of the process memory to identify security-relevant information that could be used for privilege escalation, credential theft, or exploitation of other vulnerabilities. The vulnerability's remote nature makes it particularly dangerous as it requires no local access or user interaction beyond visiting a malicious website, aligning with ATT&CK technique T1059.007 for script-based execution and T1068 for local privilege escalation through information gathering.
Mitigation strategies for this vulnerability should include immediate application of Microsoft security updates and patches, which address the underlying memory handling issues in the scripting engines. Organizations should implement browser hardening measures such as disabling unnecessary scripting capabilities, using enhanced security configurations, and deploying web application firewalls to filter malicious content. Additionally, network monitoring should be enhanced to detect anomalous memory access patterns or unusual data exfiltration attempts that might indicate exploitation of this vulnerability. The remediation process should also include comprehensive vulnerability scanning to identify systems running affected scripting engine versions and implementing proper access controls to limit exposure of sensitive data within memory spaces.