CVE-2011-1281 in Windows
Summary
by MITRE
The Client/Server Run-time Subsystem (aka CSRSS) in the Win32 subsystem in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 does not properly restrict the number of console objects for a process, which allows local users to gain privileges or cause a denial of service (memory corruption) via a crafted application that triggers an incorrect memory assignment for a user transaction, aka "CSRSS Local EOP AllocConsole Vulnerability."
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Analysis
by VulDB Data Team • 03/19/2021
The CVE-2011-1281 vulnerability represents a critical flaw in the Windows operating system's Client/Server Run-time Subsystem that has significant implications for system security and stability. This vulnerability specifically targets the Win32 subsystem component that manages console objects and user transactions within the Windows operating environment. The flaw exists in multiple versions of Windows including XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, as well as Windows 7 Gold and SP1, making it a widespread concern across the Windows ecosystem. The vulnerability is classified under CWE-121 as a buffer overflow condition, specifically involving improper restriction of operations within a memory buffer, which directly relates to the improper handling of console object allocation.
The technical mechanism behind this vulnerability involves the improper restriction of console object allocation within the CSRSS process. When a crafted application attempts to allocate console objects, the system fails to properly enforce limits on the number of console objects that can be created for a single process. This incorrect memory assignment for user transactions leads to memory corruption that can be exploited by local attackers to either escalate privileges or cause denial of service conditions. The vulnerability exploits the inherent weakness in how the system manages console object references and memory allocation within the CSRSS subsystem, which is responsible for managing console windows and user input/output operations. This flaw allows attackers to manipulate the memory layout of the CSRSS process through carefully crafted console allocation requests.
The operational impact of CVE-2011-1281 is substantial as it provides local attackers with potential paths to privilege escalation or system instability. The memory corruption that occurs when console objects are improperly allocated can result in the execution of arbitrary code with elevated privileges, potentially allowing attackers to gain SYSTEM-level access to compromised systems. Additionally, the vulnerability can be leveraged to cause denial of service conditions by exhausting system resources through excessive console object allocation, leading to system crashes or application failures. The attack surface is particularly concerning because the vulnerability exists in the core Windows subsystem that handles console operations, making it accessible to any local user with the ability to run applications on the target system. This type of vulnerability is particularly dangerous in enterprise environments where local privilege escalation can provide attackers with access to sensitive data and system resources.
Mitigation strategies for CVE-2011-1281 should focus on both immediate patching and operational security measures. Microsoft released security updates that addressed the vulnerability by implementing proper bounds checking for console object allocation within the CSRSS subsystem. Organizations should prioritize applying the relevant security patches as soon as possible to prevent exploitation. System administrators should also implement monitoring for unusual console object allocation patterns that might indicate exploitation attempts. The vulnerability's classification under ATT&CK technique T1068 suggests that attackers may leverage this weakness as part of privilege escalation tactics, making it essential to monitor for such activities. Additional defensive measures include implementing least privilege principles to limit local user capabilities, disabling unnecessary console applications, and conducting regular security assessments to identify potential exploitation attempts. Network segmentation and application whitelisting can also help reduce the attack surface for this vulnerability. The fundamental weakness in the CSRSS subsystem highlights the importance of proper memory management and bounds checking in core operating system components, as outlined in industry best practices for secure coding and system design.