CVE-2012-10021 in DIR-605L
Summary
by MITRE • 07/31/2025
A stack-based buffer overflow vulnerability exists in D-Link DIR-605L Wireless N300 Cloud Router firmware versions 1.12 and 1.13 via the getAuthCode() function. The flaw arises from unsafe usage of sprintf() when processing user-supplied CAPTCHA data via the FILECODE parameter in /goform/formLogin. A remote unauthenticated attacker can exploit this to execute arbitrary code with root privileges on the device.
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Analysis
by VulDB Data Team • 09/24/2025
The CVE-2012-10021 vulnerability represents a critical stack-based buffer overflow flaw in D-Link DIR-605L Wireless N300 Cloud Router firmware versions 1.12 and 1.13. This vulnerability resides within the getAuthCode() function that processes user-supplied CAPTCHA data through the FILECODE parameter in the /goform/formLogin endpoint. The flaw demonstrates a classic security weakness where developers failed to properly validate input length before performing string operations, creating an exploitable condition that can be leveraged by remote attackers without authentication requirements. The vulnerability operates under the CWE-121 stack-based buffer overflow category, which specifically addresses situations where data written to a stack buffer exceeds the buffer's allocated size, potentially overwriting adjacent memory locations including return addresses and control data.
The technical implementation of this vulnerability stems from the insecure usage of the sprintf() function, which does not perform bounds checking on the destination buffer. When processing the FILECODE parameter from the HTTP request, the firmware fails to validate the length of user-supplied data against the buffer size allocated for the operation. This allows an attacker to supply malicious input that exceeds the buffer capacity, causing a stack overflow condition that can be manipulated to overwrite the return address of the calling function. The attack vector is particularly dangerous because it operates over the network without requiring authentication, making it accessible to any remote attacker with basic network connectivity to the device. The vulnerability specifically targets the router's web interface authentication mechanism, potentially allowing complete system compromise with root privileges.
The operational impact of CVE-2012-10021 extends far beyond simple remote code execution, as it provides attackers with complete administrative control over the affected router. This compromised device can then serve as a pivot point for network reconnaissance, traffic interception, and potential lateral movement within the local network. The vulnerability creates a persistent backdoor that remains active until the firmware is updated, making it particularly attractive to threat actors seeking long-term access to network infrastructure. From an attacker's perspective, this vulnerability aligns with the MITRE ATT&CK framework's technique T1071.004 for application layer protocol usage, as it exploits HTTP-based web interface protocols to achieve unauthorized access. The compromised router can facilitate various malicious activities including DNS tunneling, SSH or HTTP proxy establishment, and can serve as a command and control node for botnet operations.
Mitigation strategies for CVE-2012-10021 must address both immediate remediation and long-term security posture improvements. The primary and most effective mitigation involves updating the router firmware to a version that properly validates input parameters and implements bounds checking in the sprintf() operations. Network administrators should also implement network segmentation and access control measures to limit the potential impact of exploitation. The vulnerability demonstrates the importance of input validation practices and proper secure coding techniques, aligning with industry standards such as the OWASP Top Ten and the CERT Secure Coding Standards. Organizations should conduct comprehensive vulnerability assessments to identify similar insecure coding patterns in other network devices and firmware components. Additionally, implementing network monitoring solutions that can detect anomalous traffic patterns or unauthorized access attempts can provide early warning of exploitation attempts. The vulnerability serves as a critical reminder of the importance of firmware security updates and the risks associated with legacy network infrastructure that may not receive ongoing security support from manufacturers.