CVE-2019-8317 in DIR-878
Summary
by MITRE
An issue was discovered on D-Link DIR-878 devices with firmware 1.12A1. This issue is a Command Injection allowing a remote attacker to execute arbitrary code, and get a root shell. A command Injection vulnerability allows attackers to execute arbitrary OS commands via a crafted /HNAP1 POST request. This occurs when any HNAP API function triggers a call to the system function with untrusted input from the request body for the SetStaticRouteIPv6Settings API function, as demonstrated by shell metacharacters in the DestNetwork field.
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Analysis
by VulDB Data Team • 07/10/2023
The CVE-2019-8317 vulnerability represents a critical command injection flaw in D-Link DIR-878 routers running firmware version 1.12A1, exposing devices to remote code execution attacks that can escalate to full system compromise. This vulnerability resides within the HNAP (Home Network Application Protocol) implementation of the router's web interface, specifically targeting the SetStaticRouteIPv6Settings API function. The flaw allows attackers to inject malicious commands through crafted HTTP POST requests to the /HNAP1 endpoint, where input validation is insufficient to prevent dangerous metacharacters from being processed by the underlying operating system. The vulnerability demonstrates a classic command injection pattern where user-supplied data flows directly into system calls without proper sanitization or escaping mechanisms, creating a direct pathway for arbitrary code execution at the highest privilege level.
The technical exploitation of this vulnerability follows a well-documented attack pattern that aligns with CWE-77 and CWE-94 categories, representing command injection and code injection weaknesses respectively. Attackers can leverage this flaw by crafting a malicious HNAP request that includes shell metacharacters within the DestNetwork field parameter of the SetStaticRouteIPv6Settings function. When the router processes this request, the unvalidated input gets passed directly to the system() function, enabling attackers to execute arbitrary commands with root privileges. The vulnerability's remote nature means that an attacker does not require physical access or local network presence to exploit it, making it particularly dangerous for devices accessible over the internet. This attack vector directly maps to ATT&CK technique T1059.001 for command and scripting interpreter, specifically shell commands, and T1068 for exploit for privilege escalation.
The operational impact of this vulnerability extends far beyond simple remote code execution, as it provides attackers with complete control over the affected router's functionality and access to all connected network resources. A successful exploitation allows attackers to establish persistent backdoors, modify network routing configurations, intercept traffic, or use the compromised device as a pivot point for attacking other systems within the local network. The vulnerability affects not just individual devices but potentially entire network infrastructures, as compromised routers can serve as entry points for broader network infiltration. Network administrators face significant challenges in detecting such attacks since legitimate HNAP traffic patterns remain unchanged, making the compromise nearly invisible to standard network monitoring tools. The root shell access granted by this vulnerability enables attackers to modify firmware, install malicious software, or completely disable network services, effectively rendering the device useless for its intended security purposes.
Mitigation strategies for CVE-2019-8317 must address both immediate remediation and long-term security improvements to prevent similar vulnerabilities from emerging in the future. The primary recommendation involves updating the router firmware to the latest version provided by D-Link, which should include proper input validation and sanitization measures for all HNAP API functions. Network segmentation and firewall rules should be implemented to restrict access to the router's web interface and HNAP endpoints from untrusted networks, while also limiting access to only necessary internal systems. Regular security audits should include comprehensive testing of API endpoints for command injection vulnerabilities, utilizing automated scanning tools alongside manual penetration testing approaches. Organizations should implement network monitoring solutions capable of detecting anomalous HNAP traffic patterns and establish incident response procedures specifically tailored for router compromise scenarios. The vulnerability also highlights the importance of secure coding practices, particularly input validation and output encoding, as recommended in OWASP Top 10 and NIST Cybersecurity Framework guidelines, emphasizing that proper sanitization of user inputs is fundamental to preventing command injection attacks across all network devices and applications.