CVE-2021-34828 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 buffer. An attacker can leverage this vulnerability to execute code in the context of the device. Was ZDI-CAN-12066.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/19/2021
This vulnerability represents a critical buffer overflow flaw in D-Link DAP-1330 wireless routers running firmware version 1.13B01 BETA, classified under CWE-121 as a stack-based buffer overflow condition. The vulnerability exists within the SOAPAction HTTP header processing mechanism, where the device fails to properly validate the length of user-supplied data before copying it into a fixed-length buffer. This allows an attacker to overflow the buffer and potentially overwrite adjacent memory locations, leading to arbitrary code execution with the privileges of the affected device. The vulnerability is particularly concerning because it requires no authentication, making it accessible to network-adjacent attackers who can exploit it remotely without prior access credentials. The attack surface is significant as the router's web interface and SOAP services are typically exposed to local network traffic, creating numerous potential entry points for exploitation. This flaw directly maps to ATT&CK technique T1210, which involves exploiting weaknesses in remote services to gain unauthorized access and execute malicious code on target systems.
The technical implementation of this vulnerability involves the device's SOAP service handling where the SOAPAction header is processed without adequate bounds checking. When a maliciously crafted SOAPAction header exceeds the allocated buffer size, the excess data overflows into adjacent memory regions, potentially corrupting the stack and allowing an attacker to redirect execution flow. The fixed-length buffer allocation creates a predictable attack vector where an attacker can craft a payload of specific length to overwrite return addresses or function pointers. This type of vulnerability is particularly dangerous in embedded networking equipment because it can provide persistent access to the device and potentially enable further attacks against the local network. The vulnerability's exploitation capability extends beyond simple code execution to include potential privilege escalation and persistent backdoor installation, as the device's root privileges are typically required for such operations.
The operational impact of this vulnerability extends far beyond individual device compromise, as compromised routers can serve as launching points for broader network attacks and provide persistent access to internal network resources. Network-adjacent attackers can leverage this vulnerability to establish command and control channels, perform man-in-the-middle attacks, or use the compromised device as a pivot point for attacking other systems within the local network. The vulnerability's presence in a wireless access point makes it particularly dangerous as it can affect wireless network security and potentially provide attackers with access to sensitive network communications. Organizations using affected D-Link routers face significant risk of unauthorized network access, data exfiltration, and potential disruption of network services, especially in environments where wireless access points are critical infrastructure components. This vulnerability also highlights the importance of secure coding practices and proper input validation in embedded systems, as demonstrated by the lack of proper bounds checking in the SOAPAction header processing.
Mitigation strategies for this vulnerability should include immediate firmware updates from D-Link to address the buffer overflow condition, network segmentation to limit the attack surface, and monitoring for suspicious SOAP traffic patterns. Organizations should implement network access controls to restrict access to router management interfaces and consider disabling unnecessary SOAP services when not required. The vulnerability also underscores the need for regular security assessments of network infrastructure devices and the importance of maintaining up-to-date security patches. Security teams should monitor for exploitation attempts through network traffic analysis and implement intrusion detection systems that can identify malicious SOAPAction headers. Additionally, organizations should consider implementing network behavior monitoring to detect anomalous activities that might indicate exploitation of this vulnerability, as the attack may not be immediately apparent through standard network monitoring tools. The vulnerability serves as a reminder of the critical importance of secure software development practices and the need for thorough security testing of network infrastructure devices before deployment.