CVE-2015-2440 in Windows
Summary
by MITRE
Microsoft XML Core Services 3.0, 5.0, and 6.0 allows remote attackers to bypass the ASLR protection mechanism via a crafted web site, aka "MSXML Information Disclosure Vulnerability."
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/09/2022
Microsoft XML Core Services represents a critical component in Windows operating systems that handles XML data processing and parsing operations across various applications and services. The vulnerability described in CVE-2015-2440 specifically targets the ASLR (Address Space Layout Randomization) protection mechanism within MSXML versions 3.0, 5.0, and 6.0, creating a significant security risk for affected systems. This flaw enables remote attackers to execute information disclosure attacks that bypass fundamental memory protection mechanisms designed to prevent exploitation of memory corruption vulnerabilities.
The technical flaw in this vulnerability stems from how MSXML handles certain XML parsing operations that can be manipulated to predict memory layout addresses used by the ASLR protection system. When a malicious website is crafted with specific XML structures and processing instructions, it can trigger memory access patterns that reveal information about the memory layout of the target system. This information disclosure allows attackers to overcome ASLR protections that randomize memory addresses to prevent exploitation of buffer overflows and other memory corruption vulnerabilities. The vulnerability operates at the application layer and leverages the inherent design characteristics of XML processing within MSXML to expose memory layout information that would normally be randomized and unpredictable.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally weakens the security posture of systems running affected MSXML versions. Attackers can use this information to craft more sophisticated exploits that would otherwise be impossible due to ASLR protections. This vulnerability affects systems where MSXML is used for processing untrusted XML data, including web applications, email clients, and various enterprise applications that rely on XML parsing capabilities. The attack vector requires only a malicious website to be visited by an unsuspecting user, making it particularly dangerous in phishing scenarios and drive-by download attacks. Systems with MSXML 3.0, 5.0, and 6.0 installations are at risk, though the vulnerability is most prevalent in older Windows versions and legacy applications that have not been updated.
Mitigation strategies for CVE-2015-2440 should prioritize immediate patching of affected MSXML components through Microsoft security updates. Organizations must ensure that all systems running MSXML 3.0, 5.0, and 6.0 are updated to versions that include the ASLR bypass protections. Network administrators should consider implementing additional security controls such as web application firewalls and content filtering solutions to prevent access to known malicious websites. The vulnerability aligns with CWE-200 (Information Disclosure) and represents a specific implementation weakness in memory protection mechanisms. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: Windows Command Shell) and T1071.004 (Application Layer Protocol: DNS) as attackers may use information disclosure to prepare more sophisticated attacks. Additionally, organizations should implement comprehensive monitoring for unusual XML processing activities and consider disabling unnecessary XML parsing capabilities in applications where such functionality is not essential for core operations.