CVE-2011-1268 in Windows
Summary
by MITRE
The SMB client 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 allows remote SMB servers to execute arbitrary code via a crafted (1) SMBv1 or (2) SMBv2 response, aka "SMB Response Parsing Vulnerability."
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Analysis
by VulDB Data Team • 03/19/2021
The vulnerability identified as CVE-2011-1268 represents a critical flaw in the Server Message Block protocol implementation across multiple Microsoft Windows operating systems. This vulnerability affects Windows XP Service Pack 2 and 3, Windows Server 2003 Service Pack 2, Windows Vista Service Pack 1 and 2, Windows Server 2008 Gold, SP2, R2, and R2 SP1, as well as Windows 7 Gold and SP1. The flaw resides in how these systems process SMB responses from remote servers, creating a pathway for remote code execution attacks that can be exploited by malicious actors without requiring authentication.
The technical nature of this vulnerability stems from improper parsing of SMB protocol responses, specifically when the client receives malformed or crafted SMBv1 and SMBv2 responses from malicious servers. When a vulnerable Windows system processes these malformed responses, the SMB client implementation fails to properly validate the incoming data structure, leading to memory corruption that can be exploited to execute arbitrary code with the privileges of the targeted system. This represents a classic buffer overflow condition where insufficient input validation allows attackers to manipulate memory layout and control program execution flow.
The operational impact of CVE-2011-1268 is severe and far-reaching, as it enables attackers to gain complete control over vulnerable systems without requiring user interaction or authentication. The vulnerability can be exploited through various attack vectors including network-based exploitation, where attackers can craft malicious SMB responses to be sent to vulnerable clients. This makes it particularly dangerous in enterprise environments where Windows systems may be exposed to untrusted networks or where users might inadvertently connect to malicious SMB servers. The attack can result in full system compromise, data exfiltration, lateral movement within networks, and establishment of persistent backdoors.
Mitigation strategies for this vulnerability should encompass multiple layers of defense as outlined in the MITRE ATT&CK framework for Windows SMB exploitation techniques. Immediate patching of affected systems represents the primary defense mechanism, with Microsoft releasing security updates to address the vulnerability. Network segmentation and firewall rules can be implemented to restrict SMB traffic between trusted networks and untrusted environments. Additionally, disabling SMBv1 protocol where possible reduces attack surface, as the vulnerability affects both SMBv1 and SMBv2 implementations. Security monitoring should focus on detecting unusual SMB traffic patterns and potential exploitation attempts, with network intrusion detection systems configured to alert on malformed SMB responses. Organizations should also implement principle of least privilege, ensuring that user accounts have minimal necessary permissions to reduce potential impact from successful exploitation. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and maps to ATT&CK technique T1077 for Windows remote execution through SMB/CIFS protocols, emphasizing the need for comprehensive security measures across network infrastructure and endpoint protection.