CVE-2018-17867 in H660GW
Summary
by MITRE
The Port Forwarding functionality on DASAN H660GW devices allows remote attackers to execute arbitrary code via shell metacharacters in the cgi-bin/adv_nat_virsvr.asp Addr parameter (aka the Local IP Address field).
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 03/28/2020
The vulnerability identified as CVE-2018-17867 resides within the Port Forwarding functionality of DASAN H660GW devices, representing a critical security flaw that enables remote code execution through improper input validation. This vulnerability specifically targets the cgi-bin/adv_nat_virsvr.asp web interface component where the Addr parameter, also known as the Local IP Address field, fails to properly sanitize user-supplied data. The absence of adequate input filtering creates a direct path for malicious actors to inject shell metacharacters that can be interpreted and executed by the underlying operating system.
The technical exploitation of this vulnerability follows a well-defined pattern that aligns with common web application attack vectors and maps directly to CWE-77 which describes "Improper Neutralization of Special Elements used in a Command ('Command Injection'). The flaw occurs when user input containing shell metacharacters such as semicolons, ampersands, or backticks is passed directly to system commands without proper sanitization or escaping mechanisms. This allows attackers to chain commands and execute arbitrary code with the privileges of the web server process, which typically runs with elevated permissions on network devices.
The operational impact of this vulnerability extends beyond simple code execution to encompass full system compromise and potential network infiltration. An attacker who successfully exploits this vulnerability gains the ability to execute commands remotely without authentication, potentially leading to complete device takeover, data exfiltration, or use as a pivot point for attacking other systems within the network. The vulnerability affects DASAN H660GW devices specifically, though similar patterns may exist in other network appliances that employ similar port forwarding implementations and fail to validate user inputs properly.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.001 which covers "Command and Scripting Interpreter: PowerShell" and T1068 which addresses "Exploitation for Privilege Escalation." The attack surface is particularly concerning because it operates at the network device level where attackers can leverage the compromised device to establish persistent access, create backdoors, or use the device as a launching point for broader network attacks. Organizations utilizing these devices face significant risk of unauthorized network access, data breaches, and potential compromise of their entire network infrastructure.
Mitigation strategies for this vulnerability require immediate implementation of firmware updates from DASAN, as the manufacturer would have likely released patches addressing the input validation issue. Network segmentation and access control measures should be implemented to limit exposure, while monitoring systems should be deployed to detect suspicious command execution patterns. Additionally, network administrators should consider implementing web application firewalls and input validation rules to prevent similar vulnerabilities from being exploited in other applications. The remediation process must include comprehensive testing to ensure that the patch does not introduce compatibility issues with existing network configurations while maintaining the device's operational functionality.