CVE-2010-1891 in Windows
Summary
by MITRE
The Client/Server Runtime Subsystem (aka CSRSS) in the Win32 subsystem in Microsoft Windows XP SP2 and SP3 and Server 2003 SP2, when a Chinese, Japanese, or Korean locale is enabled, does not properly allocate memory for transactions, which allows local users to gain privileges via a crafted application, aka "CSRSS Local Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability identified as CVE-2010-1891 resides within the Client/Server Runtime Subsystem component of Microsoft Windows operating systems, specifically affecting Windows XP Service Pack 2 and 3 along with Windows Server 2003 Service Pack 2. This flaw manifests when systems are configured with Chinese, Japanese, or Korean language locales, creating a critical security gap that can be exploited by local attackers to escalate their privileges from standard user level to system level access. The CSRSS process serves as a fundamental component in Windows that manages console windows and handles various system-level operations, making it a prime target for privilege escalation attacks. The vulnerability stems from improper memory allocation handling during transaction processing within the Win32 subsystem, creating opportunities for attackers to manipulate memory structures and execute malicious code with elevated privileges. This issue represents a classic example of a memory corruption vulnerability that directly impacts Windows kernel-level operations and system security boundaries.
The technical flaw within CSRSS occurs during the handling of international character sets and locale-specific processing when Chinese, Japanese, or Korean languages are enabled. The subsystem fails to properly validate or allocate memory spaces for transaction operations, leading to potential memory corruption scenarios that can be exploited through carefully crafted applications. When a user with a non-English locale is logged into the system, the CSRSS process attempts to manage character encoding and translation processes that involve complex memory management operations. The improper allocation mechanism allows attackers to manipulate the memory layout in ways that can cause the system to execute arbitrary code with kernel-level privileges. This vulnerability operates under the Common Weakness Enumeration category of CWE-129, which deals with insufficient validation of length of buffers, and more specifically relates to improper handling of memory allocation in system-level processes. The flaw enables attackers to leverage the existing system processes to gain unauthorized access to critical system resources and execute commands with the highest level of system permissions.
The operational impact of this vulnerability is severe as it allows local attackers to bypass standard security controls and escalate their privileges without requiring remote network access or complex exploitation techniques. Once successfully exploited, the attacker gains complete control over the affected system, enabling them to access all files, modify system configurations, install malicious software, and potentially use the compromised system as a launch point for further attacks within the network. The vulnerability is particularly concerning because it requires no special network connectivity or complex attack vectors, as the exploit can be executed locally on the target system itself. This characteristic makes it particularly dangerous in environments where local access is possible, such as shared workstations, terminal servers, or systems where users have legitimate local access but should not possess administrative privileges. The vulnerability can be exploited through various means including malicious applications, scripts, or even social engineering techniques that convince users to execute specific programs on the affected system.
Mitigation strategies for CVE-2010-1891 involve several layers of defensive measures that align with established cybersecurity frameworks and best practices. Microsoft has released security patches and updates that address the memory allocation issues within CSRSS, and system administrators should immediately apply the relevant security updates to all affected systems. The vulnerability can be mitigated by disabling unnecessary locale support or by implementing strict access controls that limit local user privileges and prevent unauthorized execution of potentially malicious applications. Organizations should also consider implementing application whitelisting policies that restrict execution of unsigned or untrusted applications that could exploit this vulnerability. From an operational security standpoint, regular monitoring of system logs for unusual privilege escalation activities and implementing robust endpoint protection solutions can help detect and prevent exploitation attempts. The vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and demonstrates how local privilege escalation vulnerabilities can be leveraged to achieve system compromise. Additionally, organizations should conduct regular vulnerability assessments and penetration testing to identify systems running vulnerable versions of Windows and ensure that all security patches are properly deployed across their infrastructure.