CVE-2021-34827 in DAP-1330
Summary
by MITRE • 07/16/2021
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DAP-1330 1.13B01 BETA routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of the SOAPAction HTTP header. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the device. Was ZDI-CAN-12029.
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Analysis
by VulDB Data Team • 07/19/2021
The vulnerability identified as CVE-2021-34827 represents a critical buffer overflow flaw in D-Link DAP-1330 1.13B01 BETA routers that exposes devices to remote code execution without requiring authentication. This weakness exists within the router's web service implementation and specifically targets the SOAPAction HTTP header processing mechanism. The vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue where insufficient input validation leads to data being copied beyond the bounds of a fixed-size buffer. The attack vector is particularly concerning as it requires only network adjacency, meaning an attacker positioned within the same network segment can exploit this vulnerability without needing to authenticate to the device.
The technical implementation of this flaw occurs when the router processes incoming HTTP requests containing a malformed SOAPAction header. The device fails to validate the length of user-supplied data before copying it into a fixed-length stack buffer, creating an exploitable condition where malicious input can overwrite adjacent memory locations. This buffer overflow vulnerability allows an attacker to manipulate the program execution flow by overwriting return addresses, function pointers, or other critical memory structures. The exploitation process typically involves crafting a specially formatted HTTP request with an oversized SOAPAction header that triggers the buffer overflow condition. According to ATT&CK framework, this vulnerability maps to T1210 Exploitation of Remote Services and T1059 Command and Scripting Interpreter, as successful exploitation enables arbitrary code execution on the affected device.
The operational impact of this vulnerability is severe for any organization relying on D-Link DAP-1330 routers, as it provides attackers with complete control over the affected device. Once exploited, the attacker can gain persistent access to the router's administrative interface, potentially leading to complete network compromise. The lack of authentication requirements makes this vulnerability particularly dangerous in environments where physical network access is difficult to control, as attackers can exploit it from within the network perimeter. This vulnerability could enable attackers to modify router configurations, redirect network traffic, establish backdoors, or use the compromised device as a pivot point for further attacks within the network. The affected device operates in a privileged context, making successful exploitation equivalent to gaining root-level access to the router's operating system. Organizations should consider this vulnerability as a high-priority risk that could lead to significant security breaches, especially in environments where network segmentation is not properly implemented.
Mitigation strategies for CVE-2021-34827 should include immediate firmware updates from D-Link to address the buffer overflow condition in the SOAPAction header handling. Network administrators should implement strict network segmentation to limit the attack surface and prevent unauthorized access to network devices. Additional protective measures include deploying intrusion detection systems to monitor for suspicious HTTP requests containing oversized SOAPAction headers, implementing network access controls to restrict access to router management interfaces, and regularly auditing network device configurations. Organizations should also consider disabling unnecessary services and protocols on affected devices, particularly SOAP-based web services that are not required for normal operations. The vulnerability demonstrates the importance of proper input validation and memory safety practices in embedded systems, reinforcing industry standards that emphasize the need for secure coding practices and regular security assessments of network infrastructure devices.