CVE-2020-29381 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. Command injection can occur in "upload tftp syslog" and "upload tftp configuration" in the CLI via a crafted filename.
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Analysis
by VulDB Data Team • 12/11/2020
This vulnerability affects V-SOL OLT devices across multiple firmware versions, presenting a critical command injection flaw in the command line interface. The vulnerability specifically manifests in the upload tftp syslog and upload tftp configuration commands where crafted filenames can trigger arbitrary command execution on the affected devices. This represents a significant security weakness that allows attackers to execute malicious commands with the privileges of the affected system, potentially leading to complete system compromise and unauthorized access to network infrastructure.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the CLI processing logic of these network devices. When users provide filenames for TFTP upload operations, the system fails to properly validate or escape special characters that could be interpreted as command delimiters or operators. This flaw aligns with CWE-77 which describes improper neutralization of special elements used in commands, and CWE-94 which covers improper control of generation of code, commonly known as code injection vulnerabilities. The vulnerability enables attackers to inject malicious commands that are subsequently executed by the device's underlying operating system, bypassing normal authentication and authorization mechanisms.
The operational impact of this vulnerability extends beyond simple command execution to encompass complete network infrastructure compromise. Attackers can leverage this vulnerability to gain unauthorized access to sensitive network configuration data, modify system settings, install backdoors, or redirect network traffic. Given that these are OLT (Optical Line Terminal) devices that form the backbone of fiber optic networks, the potential for widespread disruption is significant. The vulnerability could enable attackers to disrupt services, steal sensitive network information, or create persistent access points within the network infrastructure. This type of vulnerability falls under the ATT&CK technique T1059.001 for Command and Scripting Interpreter, specifically targeting the command line interface of network devices.
Mitigation strategies should focus on immediate firmware updates from V-SOL to address the root cause of the vulnerability. Network administrators should implement network segmentation and access controls to limit exposure of these devices to untrusted networks. Additionally, monitoring for suspicious TFTP upload activities and implementing network intrusion detection systems can help identify exploitation attempts. The principle of least privilege should be applied to limit who can access these CLI functions, and regular security audits should verify that no unauthorized modifications have occurred. Organizations should also consider implementing network access control lists to restrict TFTP traffic to authorized sources only, preventing unauthorized upload operations that could exploit this vulnerability.