CVE-2018-6827 in Clock
Summary
by MITRE
VOBOT CLOCK before 0.99.30 devices do not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information, and consequently execute arbitrary code, via a crafted certificate, as demonstrated by leveraging a hardcoded --no-check-certificate Wget option.
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Analysis
by VulDB Data Team • 01/03/2020
The vulnerability identified as CVE-2018-6827 affects VOBOT CLOCK devices running firmware versions prior to 09930, representing a critical security flaw in the device's SSL/TLS certificate verification mechanism. This weakness stems from the device's failure to properly validate X.509 certificates presented by SSL servers during secure communications, creating a fundamental breach in the device's security architecture. The flaw essentially disables the certificate validation process that is standard in secure communication protocols, leaving devices susceptible to malicious actors who can establish fraudulent connections with the device. This vulnerability directly violates the core principles of secure communication as defined by industry standards and best practices, creating an attack surface that can be exploited for serious security incidents.
The technical implementation of this vulnerability manifests through the device's reliance on a hardcoded --no-check-certificate option within its Wget utility, which is used for retrieving files over HTTPS. This configuration effectively bypasses all certificate validation checks that would normally occur during SSL/TLS handshakes, allowing attackers to present any certificate to the device without detection. The attack vector leverages man-in-the-middle techniques where adversaries can intercept communications between the device and legitimate servers, presenting forged certificates that the device accepts without verification. This flaw creates a persistent security weakness that can be exploited to gain unauthorized access to the device's communication channels and potentially compromise the entire system. The vulnerability aligns with CWE-295, which specifically addresses improper certificate validation, and represents a classic example of how hardcoded insecure configurations can undermine security protocols.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates opportunities for full system compromise through arbitrary code execution capabilities. Attackers who successfully exploit this vulnerability can manipulate device communications, potentially redirecting traffic to malicious servers or intercepting sensitive data transmitted by the device. The implications are particularly severe for IoT devices like VOBOT CLOCK, which may be deployed in environments where they handle sensitive information or control critical infrastructure components. The vulnerability's exploitation can lead to complete system compromise, allowing attackers to install persistent backdoors, modify device functionality, or use the compromised device as a pivot point for attacking other systems within the network. This represents a significant risk to enterprise security and aligns with ATT&CK technique T1071.004 for application layer protocol tunneling and T1059.001 for command and scripting interpreter.
Mitigation strategies for CVE-2018-6827 require immediate firmware updates to versions 0.99.30 or later, which address the certificate verification flaw by implementing proper X.509 validation mechanisms. Organizations should also conduct comprehensive inventory assessments to identify all affected devices within their networks and ensure proper certificate management practices are implemented. Network segmentation and monitoring should be enhanced to detect anomalous communications patterns that might indicate exploitation attempts. Additionally, device administrators should implement proper certificate pinning mechanisms where possible and establish robust network security controls including intrusion detection systems to monitor for man-in-the-middle attacks. The vulnerability serves as a reminder of the critical importance of secure coding practices and proper certificate validation in embedded systems, particularly in IoT deployments where device security is paramount. Regular security assessments and vulnerability scanning should be implemented to identify similar insecure configurations across the organization's device inventory.