CVE-2016-7816 in Kintone Mobile
Summary
by MITRE
The Cybozu kintone mobile for Android 1.0.6 and earlier does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
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Analysis
by VulDB Data Team • 10/15/2019
The vulnerability identified as CVE-2016-7816 affects the Cybozu kintone mobile application for Android versions 1.0.6 and earlier, representing a critical security flaw in the application's SSL/TLS certificate verification mechanism. This issue falls under the category of weak cryptographic practices and certificate validation failures, which can severely compromise the security of mobile applications that handle sensitive data. The vulnerability is particularly concerning as it affects a mobile productivity application that likely processes confidential business information, making it a prime target for cybercriminals seeking to intercept and manipulate data communications.
The technical flaw stems from the application's failure to properly validate X.509 certificates during SSL/TLS connections, which constitutes a direct violation of standard security protocols designed to establish trust between client and server. When an application does not verify server certificates, it creates an attack surface where malicious actors can perform man-in-the-middle attacks by presenting forged certificates that appear legitimate to the unverified client. This vulnerability directly maps to CWE-295, which specifically addresses improper certificate validation, and represents a fundamental failure in the application's security architecture that undermines the entire SSL/TLS security model. The lack of certificate pinning or proper validation mechanisms means that the application cannot distinguish between legitimate servers and malicious impostors, effectively disabling the cryptographic protection intended to secure communications.
The operational impact of this vulnerability extends beyond simple data interception, as it enables attackers to not only eavesdrop on communications but also to actively manipulate data flows and potentially inject malicious content into the application's communication channels. Mobile applications like kintone that handle business-critical information are particularly vulnerable to such attacks, as they often process sensitive corporate data, personal information, and confidential business communications. The man-in-the-middle attack vector allows threat actors to obtain sensitive information through crafted certificates, potentially compromising user credentials, business data, and proprietary information. This vulnerability is classified under the MITRE ATT&CK framework's T1041 technique for Exfiltration Over C2 Channel, as well as T1566 for Phishing, since the attack can be executed through certificate manipulation that may be indistinguishable from legitimate network traffic to end users.
Mitigation strategies for this vulnerability should focus on implementing proper certificate validation mechanisms within the mobile application, including certificate pinning, certificate chain validation, and implementation of robust SSL/TLS security configurations. Organizations should immediately update to the latest version of the kintone mobile application where this vulnerability has been addressed, as the vendor likely implemented proper certificate verification mechanisms in subsequent releases. Security teams should also consider network-level protections such as SSL inspection and monitoring for suspicious certificate behavior, while implementing comprehensive network segmentation to limit the potential impact of successful attacks. The vulnerability highlights the importance of maintaining up-to-date security practices in mobile applications and demonstrates the critical need for proper cryptographic implementation in all network communications. Additionally, organizations should conduct regular security assessments of mobile applications to identify similar certificate validation issues that may exist in other applications within their environment, as this type of vulnerability is commonly found in mobile applications that prioritize user experience over security implementation.