CVE-2017-0161 in Windows
Summary
by MITRE
The Windows NetBT Session Services component on Microsoft Windows Server 2008 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 maintain certain sequencing requirements, aka "NetBIOS Remote Code Execution Vulnerability".
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/11/2021
The vulnerability identified as CVE-2017-0161 resides within the Windows NetBT Session Services component, which represents a critical security flaw in multiple Microsoft Windows operating systems including server and client versions. This vulnerability specifically affects Windows Server 2008 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 issue stems from the component's failure to properly maintain certain sequencing requirements during network communication processes, creating a pathway for malicious actors to exploit the system remotely.
The technical flaw manifests in the improper handling of NetBIOS session establishment and management protocols, where the NetBT service does not adequately validate sequence numbers or maintain proper state tracking during session creation. This weakness allows attackers to craft malicious packets that manipulate the session sequencing logic, potentially leading to arbitrary code execution on vulnerable systems. The vulnerability operates at the network transport layer, leveraging the legacy NetBIOS over TCP/IP implementation that remains enabled by default in many Windows installations. According to CWE classification, this represents a weakness in the design of network protocol handling, specifically categorized under CWE-129 as improper validation of sequence numbers and CWE-121 as buffer overflow conditions.
The operational impact of this vulnerability extends across enterprise networks where Windows systems communicate using NetBIOS protocols, particularly in environments where legacy applications or network services depend on these older communication methods. Attackers can exploit this vulnerability without authentication, making it particularly dangerous in environments where network services are accessible from external networks. The remote code execution capability allows threat actors to gain full system control, potentially leading to data exfiltration, system compromise, and lateral movement within the network. This vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol usage and T1059 for command and scripting interpreter, as exploitation typically involves executing malicious code through compromised network services.
Mitigation strategies should focus on immediate patch deployment through Microsoft's regular security updates, as well as network segmentation to limit exposure of vulnerable systems to untrusted networks. Organizations should disable NetBIOS over TCP/IP where not required, implement firewall rules to block NetBIOS ports 137 and 138, and monitor network traffic for suspicious session establishment patterns. The vulnerability demonstrates the ongoing risks associated with legacy protocol implementations and underscores the importance of maintaining up-to-date security patches across all networked systems. Additionally, security teams should conduct vulnerability assessments to identify systems that may still be using legacy NetBIOS protocols and implement proper network monitoring to detect potential exploitation attempts.