CVE-2015-6161 in Edge
Summary
by MITRE
Microsoft Internet Explorer 7 through 11 and Microsoft Edge allow remote attackers to bypass the ASLR protection mechanism via a crafted web site, aka "Microsoft Browser ASLR Bypass."
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Analysis
by VulDB Data Team • 06/29/2022
The vulnerability identified as CVE-2015-6161 represents a critical security flaw in Microsoft Internet Explorer versions 7 through 11 and Microsoft Edge browsers that compromises Address Space Layout Randomization protection mechanisms. This vulnerability falls under the CWE-1178 category of improper implementation of security features, specifically targeting memory protection mechanisms designed to prevent exploitation of memory corruption vulnerabilities. The flaw enables remote attackers to bypass ASLR, a fundamental security mitigation technique that randomizes the memory layout of processes to make exploitation of memory corruption vulnerabilities more difficult. The vulnerability is particularly concerning because it affects multiple browser versions spanning over a decade of Microsoft's browser ecosystem, providing attackers with broad exploitation opportunities across different environments and user bases.
The technical implementation of this vulnerability involves sophisticated manipulation of browser memory management and process execution flows that ultimately leads to predictable memory addresses despite ASLR being enabled. Attackers can craft malicious websites that leverage specific browser behaviors and memory layout characteristics to determine the locations of critical system components, libraries, and memory regions that would normally be randomized. This bypass occurs through manipulation of JavaScript execution contexts, memory allocation patterns, and browser-specific implementation details that allow attackers to predict or derive memory addresses that ASLR was designed to obscure. The exploitation technique typically involves leveraging information disclosure vulnerabilities or specific memory access patterns that reveal sufficient information about the memory layout to defeat the randomness provided by ASLR.
The operational impact of CVE-2015-6161 is severe and far-reaching across enterprise and individual computing environments. Organizations running affected browser versions face increased risk of successful exploitation of other vulnerabilities that would otherwise be protected against by ASLR, including buffer overflows, use-after-free conditions, and other memory corruption exploits. The vulnerability creates a pathway for attackers to escalate privileges, execute arbitrary code, and potentially gain full system control without requiring additional exploitation primitives that would normally be needed to overcome ASLR protection. This makes the vulnerability particularly dangerous in targeted attacks where attackers may combine this ASLR bypass with other exploits to achieve persistent access to systems. The long support lifecycle of affected browser versions means that many organizations continued to be exposed to this vulnerability for extended periods.
Mitigation strategies for this vulnerability include immediate deployment of Microsoft security updates and patches that address the specific ASLR bypass mechanism. Organizations should implement browser hardening measures including disabling unnecessary browser features, implementing content security policies, and using additional security layers such as exploit protection mechanisms and application whitelisting. The vulnerability highlights the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that reduce the attack surface available to threat actors. Security professionals should also consider implementing network-based protections such as web application firewalls and monitoring for suspicious browser behavior patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of keeping software updated and the potential consequences of running unsupported browser versions in enterprise environments.