CVE-2022-35619 in DIR-818LW
Summary
by MITRE • 08/03/2022
D-LINK DIR-818LW A1:DIR818L_FW105b01 was discovered to contain a remote code execution (RCE) vulnerability via the function ssdpcgi_main.
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Analysis
by VulDB Data Team • 08/30/2022
The vulnerability identified as CVE-2022-35619 affects D-Link DIR-818LW A1 routers running firmware version DIR818L_FW105b01 and represents a critical remote code execution flaw that can be exploited without authentication. This vulnerability resides within the ssdpcgi_main function, which serves as a core component of the router's web interface handling system. The issue stems from insufficient input validation and sanitization within the device's Simple Service Discovery Protocol (SSDP) implementation, creating a pathway for malicious actors to inject and execute arbitrary code on the affected device. The vulnerability impacts devices that utilize the embedded web server functionality to process network discovery requests, making it particularly dangerous in environments where these routers serve as network infrastructure components.
The technical exploitation of this vulnerability occurs through improper handling of user-supplied data within the ssdpcgi_main function, which processes incoming SSDP requests that are part of the UPnP (Universal Plug and Play) protocol implementation. When a specially crafted HTTP request is sent to the router's web interface, the vulnerable code fails to properly validate or sanitize the input parameters before processing them. This allows attackers to inject malicious commands that are subsequently executed with the privileges of the web server process, typically running with elevated system permissions. The flaw aligns with CWE-74, which describes improper neutralization of special elements in output used by a downstream component, and CWE-94, which covers improper control of generation of code. The vulnerability's classification as a remote code execution issue places it within the ATT&CK framework under the T1059.007 technique category, specifically command and scripting interpreter: python, indicating that attackers can leverage this weakness to establish persistent access to the network infrastructure.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with complete control over the affected router, enabling them to modify network configurations, redirect traffic, perform man-in-the-middle attacks, or use the device as a launching point for further attacks against internal network resources. The vulnerability affects not only the router's administrative functions but also its core networking capabilities, potentially disrupting network services or creating backdoors for future exploitation. Organizations with multiple affected devices face significant risk, as a successful exploitation on one device could provide attackers with insights into the network topology and facilitate lateral movement within the infrastructure. The vulnerability's exposure through the standard web interface makes it particularly concerning as it requires no specialized knowledge or physical access to compromise the device, representing a significant threat to both enterprise and home network security.
Mitigation strategies for this vulnerability should include immediate firmware updates from D-Link, which typically address the root cause by implementing proper input validation and sanitization within the ssdpcgi_main function. Network segmentation and access control measures can help limit the potential impact if exploitation occurs, while monitoring for unusual network traffic patterns or unauthorized configuration changes can aid in early detection of compromise attempts. Organizations should also consider implementing network intrusion detection systems that can identify and alert on suspicious SSDP or UPnP traffic patterns. The vulnerability highlights the importance of secure coding practices and proper input validation in embedded systems, particularly those handling network discovery protocols. Additionally, disabling unnecessary services such as UPnP when not required, implementing firewall rules to restrict access to the router's web interface, and conducting regular security assessments of network infrastructure can significantly reduce the attack surface and minimize the risk of exploitation.