CVE-2020-19320 in 619L
Summary
by MITRE • 09/11/2023
Buffer overflow vulnerability in DLINK 619L version B 2.06beta via the curTime parameter on login.
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Analysis
by VulDB Data Team • 10/10/2023
A buffer overflow vulnerability exists in the D-Link 619L version B 2.06beta device when processing the curTime parameter during the login authentication process. This vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking allows an attacker to write data beyond the allocated memory buffer. The flaw occurs when the device receives a specially crafted curTime parameter that exceeds the predetermined buffer size, leading to potential memory corruption and arbitrary code execution.
The technical implementation of this vulnerability involves the device's web server component failing to properly validate input length before copying the curTime parameter into a fixed-size buffer. When an attacker submits a maliciously formatted curTime value containing excessive data, the overflow can overwrite adjacent memory locations including return addresses, function pointers, and other critical control structures. This memory corruption can be exploited to redirect program execution flow and potentially gain unauthorized administrative access to the device.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it enables remote code execution capabilities that could allow attackers to completely compromise the device. An attacker could leverage this vulnerability to install malicious firmware, establish persistent backdoors, or use the compromised device as a pivot point for network reconnaissance and lateral movement attacks. The vulnerability affects all versions of the D-Link 619L running firmware version B 2.06beta and potentially exposes networks to unauthorized access through the exploitation of this authentication bypass mechanism.
Security professionals should implement immediate mitigations including firmware updates from D-Link that address the buffer overflow condition through proper input validation and bounds checking mechanisms. Network segmentation and access control measures can help limit the potential impact if exploitation occurs, while monitoring for unusual login patterns or malformed HTTP requests containing excessive curTime parameter values can aid in early detection of attempted exploitation. The vulnerability aligns with ATT&CK technique T1210 for exploiting buffer overflow vulnerabilities and represents a significant risk to network security infrastructure where unpatched embedded devices serve as entry points for broader attacks. Organizations should prioritize patching this vulnerability as it provides attackers with a straightforward path to device compromise and potential network infiltration through the exploitation of this authentication mechanism flaw.