CVE-2020-29375 in V1600D
Summary
by MITRE • 11/29/2020
An issue was discovered on V-SOL V1600D V2.03.69 and V2.03.57, V1600D4L V1.01.49, V1600D-MINI V1.01.48, V1600G1 V2.0.7 and V1.9.7, and V1600G2 V1.1.4 OLT devices. An low-privileged (non-admin) attacker can use a hardcoded password (4ef9cea10b2362f15ba4558b1d5c081f) to create an admin user.
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Analysis
by VulDB Data Team • 12/11/2020
This vulnerability affects V-SOL OLT devices across multiple product lines including V1600D, V1600D4L, V1600D-MINI, V1600G1, and V1600G2 models with specific firmware versions. The issue represents a critical privilege escalation flaw that allows low-privileged users to gain administrative access through a hardcoded credential mechanism. The hardcoded password hash 4ef9cea10b2362f15ba4558b1d5c081f provides unauthorized access to administrative functions without requiring legitimate authentication credentials.
The technical implementation of this vulnerability stems from improper security design practices where developers embedded a default password directly into the firmware code. This approach violates fundamental security principles outlined in CWE-259 and CWE-798, which specifically address the use of hardcoded credentials in software systems. The flaw exists at the authentication layer where the system fails to properly validate user credentials and instead accepts the predetermined hash value as legitimate administrative access. This represents a classic case of weak credential management and improper access control implementation.
From an operational perspective, this vulnerability creates significant risk for network infrastructure security since it allows attackers to elevate privileges from standard user level to administrator level without requiring legitimate credentials. The impact extends beyond simple privilege escalation as it enables full control over the OLT devices, potentially allowing attackers to modify network configurations, access sensitive data, disrupt services, or establish persistent backdoors. Network operators face severe operational challenges since the vulnerability remains undetected until exploitation occurs, and the hardcoded nature of the credential means it cannot be changed or removed through normal administrative procedures.
The attack surface for this vulnerability encompasses all affected V-SOL OLT devices deployed in network environments, particularly those with exposed management interfaces or accessible web administration portals. Attackers can leverage this flaw through various vectors including remote network access, physical access to devices, or through compromised network endpoints that can reach the OLT management interfaces. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and T1548 which covers abuse of privileges, demonstrating how hardcoded credentials can be exploited to maintain persistent access to network infrastructure. Organizations should immediately implement network segmentation to isolate affected devices, disable unnecessary management interfaces, and deploy network monitoring to detect unauthorized access attempts. Firmware updates from V-SOL should be applied immediately to address this vulnerability, and all affected devices should have their management interfaces secured through proper access controls and authentication mechanisms.