CVE-2017-0166 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in Windows when LDAP request buffer lengths are improperly calculated. In a remote attack scenario, an attacker could exploit this vulnerability by running a specially crafted application to send malicious traffic to a Domain Controller, aka "LDAP Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 11/28/2022
The CVE-2017-0166 vulnerability represents a critical elevation of privilege flaw within Microsoft Windows operating systems that specifically impacts the Lightweight Directory Access Protocol implementation. This vulnerability stems from improper buffer length calculations during LDAP request processing, creating a pathway for malicious actors to escalate their privileges within network environments. The flaw exists at the core of Windows domain controller functionality where LDAP requests are handled, making it particularly dangerous in enterprise environments where domain controllers serve as central authentication points. The vulnerability's classification under CWE-129 indicates improper input validation or buffer overflow conditions that allow attackers to manipulate memory boundaries during LDAP processing operations.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious LDAP request that contains malformed buffer length parameters. During the processing of such requests, Windows fails to properly validate or calculate the buffer sizes required for handling the incoming data, leading to potential memory corruption or overflow conditions. This improper buffer handling allows attackers to execute arbitrary code with elevated privileges, potentially gaining administrative access to domain controllers and subsequently compromising entire network infrastructures. The attack vector requires remote execution capabilities since the vulnerability manifests when domain controllers process LDAP requests from external sources, making it particularly concerning for organizations with exposed domain controller services.
From an operational impact perspective, this vulnerability creates a severe risk for enterprise network security as domain controllers are critical infrastructure components that maintain authentication credentials and access controls for entire organizational networks. Successful exploitation could enable attackers to establish persistent access to domain controller services, allowing them to modify user accounts, create backdoor access points, or escalate their privileges to domain administrator level. The vulnerability affects multiple Windows versions including Windows Server 2008, 2012, and 2016, making it widespread across enterprise environments. Network reconnaissance activities often reveal exposed domain controller services, creating additional attack surface that makes this vulnerability particularly attractive to threat actors. The impact extends beyond immediate privilege escalation to potential lateral movement within networks and data exfiltration capabilities.
Organizations should implement immediate mitigations including applying Microsoft security patches released in the July 2017 security updates, which address the buffer length calculation issues in LDAP processing. Network segmentation strategies should be employed to limit direct access to domain controller services, implementing firewalls and access control lists that restrict LDAP traffic to authorized systems only. Monitoring solutions should be enhanced to detect anomalous LDAP request patterns that may indicate exploitation attempts, including unusual buffer sizes or malformed requests. The vulnerability aligns with ATT&CK technique T1078 for valid accounts and T1566 for credential access through network services, making it a significant concern for organizations following MITRE ATT&CK framework assessments. Regular security audits should verify that domain controller services are not exposed to unnecessary network access and that proper network segmentation controls are in place to prevent unauthorized LDAP communications.