CVE-2017-0273 in Windows
Summary
by MITRE
The Microsoft Server Message Block 1.0 (SMBv1) allows denial of service when an attacker sends specially crafted requests to the server, aka "Windows SMB Denial of Service Vulnerability". This CVE ID is unique from CVE-2017-0269 and CVE-2017-0280.
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Analysis
by VulDB Data Team • 12/23/2020
The vulnerability identified as CVE-2017-0273 represents a critical denial of service flaw within Microsoft Server Message Block version 1.0 protocol implementation. This weakness specifically affects Windows operating systems that continue to support SMBv1 functionality, which despite being deprecated for years remains enabled by default on many enterprise systems. The vulnerability stems from insufficient input validation within the SMBv1 server component that processes incoming network requests, creating an opportunity for malicious actors to exploit the protocol's handling of malformed data structures. The issue manifests when remote attackers send specially crafted SMBv1 requests designed to trigger memory corruption or resource exhaustion conditions within the target server's SMB service implementation.
The technical exploitation of this vulnerability occurs through the manipulation of SMBv1 protocol packets that contain malformed or oversized data fields within the server message block structure. When the affected Windows system processes these crafted requests, the SMBv1 server component fails to properly validate the incoming data, leading to unpredictable behavior including system crashes, service termination, or complete system hang conditions. The flaw operates at the network protocol level where the SMBv1 implementation lacks adequate bounds checking and error handling mechanisms for processing specific request types. This vulnerability is particularly concerning because SMBv1 is a foundational protocol for file sharing and network communication in Windows environments, making it a prime target for attackers seeking to disrupt business operations.
From an operational impact perspective, this vulnerability creates significant risk for organizations that maintain SMBv1 support on their servers and workstations. The denial of service condition can result in complete disruption of file sharing services, application availability, and network connectivity for affected systems. Attackers can leverage this vulnerability to perform sustained disruption attacks that may require system restarts or manual intervention to restore normal operations. The impact extends beyond individual systems to potentially affect entire network segments where SMBv1 is utilized for critical services such as print sharing, file server access, and inter-system communication. Organizations may experience productivity losses, service interruptions, and potential revenue impacts during extended periods of system unavailability.
Security professionals should consider this vulnerability in relation to the broader ATT&CK framework where it maps to the T1499.004 technique for network denial of service attacks. The vulnerability also aligns with CWE-121 which addresses stack-based buffer overflow conditions, though this specific case involves memory corruption rather than traditional buffer overflows. Mitigation strategies should prioritize the complete disablement of SMBv1 protocol support on all Windows systems through Group Policy configuration or registry modifications. Organizations should implement network segmentation to prevent unauthorized access to systems that may still have SMBv1 enabled. Additionally, monitoring solutions should be deployed to detect unusual SMBv1 traffic patterns or malformed request sequences that could indicate exploitation attempts. The recommended remediation includes enabling SMBv2 and SMBv3 protocols while ensuring that SMBv1 is completely disabled through appropriate administrative controls and security policies.