CVE-2022-43629 in DIR-1935
Summary
by MITRE • 03/29/2023
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DIR-1935 1.03 routers. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the handling of SetSysEmailSettings requests to the web management portal. When parsing subelements within the SetSysEmailSettings element, the process does not properly validate a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-16149.
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Analysis
by VulDB Data Team • 06/13/2026
This vulnerability represents a critical remote code execution flaw in D-Link DIR-1935 routers running firmware version 1.03, where network-adjacent attackers can potentially gain full system control. The vulnerability stems from improper input validation within the web management portal's handling of SetSysEmailSettings requests, creating a dangerous condition where user-supplied data can be directly passed to system calls without adequate sanitization. The flaw exists specifically in the parsing logic of XML elements, where the system fails to properly validate or sanitize strings before executing system commands, effectively creating a command injection vulnerability that operates at the highest privilege level within the router's operating system.
The technical implementation of this vulnerability leverages the existing authentication mechanism's bypass capability, which allows attackers to circumvent the normal authentication flow and gain access to the management interface. Once authenticated, the attacker can craft malicious SetSysEmailSettings requests that contain specially formatted payloads designed to exploit the insufficient input validation. This particular vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic command injection attack vector. The attack chain begins with authentication bypass, followed by crafting malicious XML requests that exploit the vulnerable parsing logic, ultimately resulting in arbitrary code execution with root privileges.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected router's functionality and underlying system. Since the exploitation occurs with root privileges, attackers can modify network configurations, install malicious software, create backdoors, or use the compromised device as a pivot point for attacking other systems within the local network. The vulnerability's accessibility to network-adjacent attackers means that even without direct internet exposure, devices within the same network segment can be compromised, potentially enabling lateral movement attacks against other networked devices. This makes the vulnerability particularly dangerous in corporate or residential environments where multiple devices share the same network infrastructure.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from D-Link to address the specific parsing and validation flaws within the web management portal. Network administrators should implement network segmentation and access control measures to limit the potential attack surface, ensuring that only authorized personnel can access the router management interfaces. Additionally, monitoring network traffic for suspicious SetSysEmailSettings requests and implementing intrusion detection systems can help identify exploitation attempts. The vulnerability's classification under ATT&CK technique T1059.001 for command and scripting interpreter indicates that organizations should also focus on detecting unusual command execution patterns and implement strict access controls for administrative interfaces. Organizations should also consider disabling unnecessary web management services and implementing strong authentication mechanisms to reduce the likelihood of successful exploitation attempts.