CVE-2019-6963 in RDKB-20181217-1
Summary
by MITRE
A heap-based buffer overflow in cosa_dhcpv4_dml.c in the RDK RDKB-20181217-1 CcspPandM module may allow attackers with login credentials to achieve remote code execution by crafting a long buffer in the "Comment" field of an IP reservation form in the admin panel. This is related to the CcspCommonLibrary module.
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Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-6963 represents a critical heap-based buffer overflow within the RDK RDKB-20181217-1 CcspPandM module of the RDK (RDKB) platform. This flaw exists in the cosa_dhcpv4_dml.c file and specifically targets the handling of user input through the Comment field of IP reservation forms within the administrative web interface. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, which occurs when more data is written to a buffer allocated on the heap than the buffer can accommodate, leading to memory corruption that can be exploited for arbitrary code execution. The issue is particularly concerning because it requires only valid login credentials to exploit, making it accessible to authenticated attackers who can leverage their administrative privileges to craft malicious payloads.
The technical implementation of this vulnerability stems from improper bounds checking within the CcspCommonLibrary module that processes DHCPv4 reservations. When administrators input data into the Comment field of an IP reservation form, the system fails to validate the length of the input string before copying it into a fixed-size heap buffer. This oversight allows attackers to exceed the buffer boundaries and overwrite adjacent memory locations, potentially corrupting critical data structures or executable code. The attack vector is facilitated through the web administration panel, where the vulnerability is triggered during the processing of DHCP reservation requests, making it a classic example of a command injection vulnerability that can be exploited through user-controllable input fields. The exploitation process typically involves crafting a specially formatted Comment field containing a payload that overflows the designated buffer and redirects program execution flow.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables full remote code execution on the affected device with the privileges of the authenticated administrative user. This capability allows attackers to gain complete control over the device's functionality, potentially leading to persistent access, data exfiltration, or further network infiltration. The vulnerability affects devices running the RDK platform, which is widely deployed in consumer and enterprise networking equipment, making it a significant concern for network administrators managing multiple devices. The attack scenario involves an authenticated attacker submitting a malicious Comment field value that triggers the buffer overflow, potentially leading to system compromise and unauthorized access to network resources. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, demonstrating the multi-faceted nature of the threat.
Mitigation strategies for CVE-2019-6963 should prioritize immediate patching of affected RDK implementations, as this vulnerability has been addressed in subsequent releases of the platform. Organizations should implement input validation controls that enforce strict length limits on Comment fields and other user-controllable inputs within administrative interfaces. Network segmentation and access control measures should be strengthened to limit the potential impact of successful exploitation, while monitoring systems should be configured to detect anomalous administrative activities that might indicate exploitation attempts. Additionally, regular security assessments of web-based administrative interfaces should be conducted to identify similar buffer overflow vulnerabilities, and developers should adopt secure coding practices that prevent heap-based buffer overflows through proper bounds checking and memory management. The vulnerability serves as a reminder of the importance of input validation in web applications and the critical need for regular security updates in embedded systems that serve as network infrastructure components.