CVE-2024-8748 in VMG8825-T50K
Summary
by MITRE • 12/03/2024
A buffer overflow vulnerability in the packet parser of the third-party library "libclinkc" in Zyxel VMG8825-T50K firmware versions through V5.50(ABOM.8.4)C0 could allow an attacker to cause a temporary denial of service (DoS) condition against the web management interface by sending a crafted HTTP POST request to a vulnerable device.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/03/2024
The vulnerability identified as CVE-2024-8748 represents a critical buffer overflow flaw within the packet parsing functionality of the third-party library libclinkc that is integrated into Zyxel VMG8825-T50K modem firmware versions up to and including V5.50(ABOM.8.4)C0. This issue arises from inadequate input validation and memory management practices within the library's HTTP request handling mechanisms. The affected device's web management interface becomes susceptible to exploitation when processing specially crafted HTTP POST requests that exceed allocated buffer boundaries. The vulnerability specifically targets the packet parser component responsible for interpreting incoming network traffic, creating a scenario where malicious input can overwrite adjacent memory locations and potentially disrupt normal system operations.
The technical implementation of this flaw stems from improper bounds checking during HTTP request processing within the libclinkc library. When the vulnerable firmware receives an HTTP POST request containing oversized payload data, the parsing routine fails to validate the input length against predetermined buffer limits. This condition creates an exploitable buffer overflow scenario classified under CWE-121 as a stack-based buffer overflow or CWE-122 as a heap-based buffer overflow depending on the specific memory allocation pattern. The attack vector requires minimal privileges as the vulnerability is accessible through the web interface, making it particularly concerning for network administrators and security professionals managing these devices. The flaw demonstrates a classic weakness in defensive programming practices where input validation is insufficient to prevent memory corruption during data processing operations.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack scenarios. While the immediate effect manifests as a temporary denial of service against the web management interface, the buffer overflow condition could theoretically be exploited to execute arbitrary code on the affected device. This represents a significant concern for network infrastructure devices as it could allow attackers to gain unauthorized access to the device's management functions, potentially leading to complete system compromise. The vulnerability affects devices running firmware versions through V5.50(ABOM.8.4)C0, indicating that a substantial number of installations may be at risk. The web-based nature of the attack surface means that exploitation can occur remotely without physical access to the device, aligning with ATT&CK technique T1190 for exploit via web shell and T1210 for exploitation of remote services. Network security teams must consider the potential for this vulnerability to serve as a stepping stone for broader network infiltration, particularly in environments where these devices are not properly segmented or monitored.
Mitigation strategies for CVE-2024-8748 should prioritize immediate firmware updates from Zyxel to address the underlying buffer overflow condition in libclinkc. Organizations should implement network segmentation to limit access to the affected devices and restrict web management interface access to trusted networks only. Additional protective measures include deploying intrusion detection systems capable of identifying suspicious HTTP POST traffic patterns and implementing rate limiting on web interface access to reduce the effectiveness of potential DoS attacks. Security monitoring should focus on detecting anomalous traffic patterns that might indicate exploitation attempts, particularly around the web management interface ports. Network administrators should also consider disabling unnecessary web management services when not required for administrative tasks. The vulnerability highlights the importance of third-party library security auditing and the need for robust input validation practices in embedded systems. Organizations should establish procedures for tracking and updating third-party components within their network infrastructure to prevent similar vulnerabilities from persisting across their environments. Regular security assessments and vulnerability scanning should be implemented to identify and remediate similar issues before they can be exploited by malicious actors.