CVE-2017-11780 in Windows
Summary
by MITRE
The Server Message Block 1.0 (SMBv1) on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016, allows a remote code execution vulnerability when it fails to properly handle certain requests, aka "Windows SMB Remote Code Execution Vulnerability".
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Analysis
by VulDB Data Team • 01/16/2021
The vulnerability identified as CVE-2017-11780 represents a critical remote code execution flaw within the Server Message Block version 1.0 implementation across multiple Microsoft Windows operating systems. This vulnerability specifically affects Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, as well as Windows Server 2016. The flaw manifests when the SMBv1 protocol fails to properly handle certain malformed requests, creating a pathway for malicious actors to execute arbitrary code on affected systems. This vulnerability is particularly concerning given the widespread deployment of SMBv1 across enterprise environments and the protocol's critical role in file sharing and network communication. The issue stems from improper input validation within the SMBv1 server implementation, which does not adequately sanitize incoming requests, leading to potential buffer overflows or other memory corruption conditions that can be exploited by attackers.
The technical exploitation of this vulnerability occurs through crafted SMBv1 requests that trigger memory corruption within the Windows SMB server component. When a vulnerable system processes these malformed requests, the insufficient validation allows attackers to manipulate memory structures and potentially execute malicious code with the privileges of the target system. The vulnerability is classified under CWE-121, which describes heap-based buffer overflow conditions, and specifically relates to improper handling of input data in network protocols. The attack vector requires network access to the target system, typically through port 445 or port 139, making it particularly dangerous in environments where these ports are exposed to untrusted networks. The exploitation process often involves sending specially crafted SMB packets that cause the system to allocate memory incorrectly, leading to code execution in the context of the affected service. This vulnerability is categorized under the ATT&CK technique T1075 which describes the use of remote services, and more specifically aligns with T1210 which covers exploitation of remote services for privilege escalation and code execution.
The operational impact of CVE-2017-11780 extends far beyond individual system compromise, as it provides attackers with a powerful means of establishing persistent access within networks. Once exploited, the vulnerability allows attackers to execute arbitrary code with system-level privileges, potentially enabling lateral movement, data exfiltration, and establishment of backdoors. The widespread adoption of SMBv1 across enterprise environments means that a single compromised system can serve as a foothold for broader network infiltration. Organizations running affected versions of Windows are particularly vulnerable because SMBv1 was designed without modern security considerations and continues to be enabled by default in many configurations. The vulnerability's exploitation can lead to complete system compromise, data loss, and disruption of business operations, with potential impacts extending to compliance and regulatory requirements. Security teams must consider the broader implications of this vulnerability in relation to the ATT&CK framework's T1068 technique for exploit for privilege escalation, as the vulnerability can be leveraged to gain elevated privileges and persist within target environments. The long-term consequences include the potential for attackers to establish persistent access and maintain control over compromised systems for extended periods, making the vulnerability particularly dangerous for organizations with insufficient network segmentation and monitoring capabilities.
Mitigation strategies for CVE-2017-11780 focus primarily on disabling SMBv1 functionality, which is the most effective approach given the protocol's inherent security weaknesses. Microsoft recommends disabling SMBv1 through registry modifications or group policy configurations, as this eliminates the attack surface entirely while maintaining necessary functionality through SMBv2 and SMBv3 implementations. Organizations should also implement network segmentation to limit access to SMB ports, deploy intrusion detection systems to monitor for suspicious SMB traffic, and ensure regular patching of affected systems. The mitigation process should include comprehensive vulnerability assessments to identify all systems running SMBv1, followed by systematic disabling of the protocol across the enterprise. Security controls should also address the ATT&CK technique T1046 which involves discovery of network services, as attackers may attempt to identify systems with SMBv1 enabled. Additional protective measures include implementing network access controls, monitoring for anomalous SMB traffic patterns, and maintaining up-to-date security information and event management systems to detect exploitation attempts. Organizations should also consider implementing endpoint detection and response solutions that can identify the specific exploitation patterns associated with this vulnerability, as well as ensuring that security teams are trained to recognize and respond to SMB-related attack indicators. The vulnerability's remediation requires careful planning to avoid disrupting legitimate SMBv1-dependent applications while ensuring comprehensive protection against the remote code execution threat.