CVE-2019-2766 in Java SE
Summary
by MITRE
Vulnerability in the Java SE, Java SE Embedded component of Oracle Java SE (subcomponent: Networking). Supported versions that are affected are Java SE: 7u221, 8u212, 11.0.3 and 12.0.1; Java SE Embedded: 8u211. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Java SE, Java SE Embedded. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized read access to a subset of Java SE, Java SE Embedded accessible data. Note: This vulnerability applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets (in Java SE 8), that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. This vulnerability can also be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. CVSS 3.0 Base Score 3.1 (Confidentiality impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N).
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Analysis
by VulDB Data Team • 07/06/2020
The vulnerability described in CVE-2019-2766 represents a significant security weakness within Oracle Java SE and Java SE Embedded platforms, specifically within the Networking subcomponent. This flaw affects multiple version lines including Java SE 7u221, 8u212, 11.0.3, and 12.0.1, along with Java SE Embedded 8u211, demonstrating the widespread nature of the issue across different Java release cycles. The vulnerability's classification as difficult to exploit indicates that while it requires specific conditions to be met, the attack surface remains substantial given Java's prevalence in enterprise and client environments. The CVSS 3.0 score of 3.1 reflects a low to medium severity impact, primarily focused on confidentiality concerns with no direct impact on integrity or availability.
The technical nature of this vulnerability stems from inadequate security controls within Java's networking capabilities, particularly when executing untrusted code within sandboxed environments. Attackers can exploit this weakness through network-based protocols without requiring authentication, making it particularly dangerous in environments where Java applications process data from untrusted sources. The vulnerability specifically targets Java deployments that utilize sandboxed Web Start applications or applets, which are designed to operate within restricted security boundaries. However, the flaw allows attackers to bypass these security mechanisms and gain unauthorized read access to sensitive data within the Java runtime environment. This represents a classic sandbox escape scenario where the security boundary intended to protect system resources is compromised.
The operational impact of CVE-2019-2766 extends beyond simple data confidentiality breaches, as it undermines the fundamental security model that Java applications rely upon for protection. Successful exploitation requires human interaction, suggesting that attackers must convince users to execute malicious code through social engineering or other means, but once initiated, the vulnerability can access data that should remain protected within the Java sandbox. The affected environments typically include web applications that utilize Java applets or Web Start applications, which are often deployed in enterprise settings where sensitive business data resides. This vulnerability particularly affects organizations that continue to support legacy Java applications or those that have not fully migrated away from sandboxed Java technologies. The implications are significant for organizations maintaining Java-based systems that process confidential information, as the attack vector can be leveraged through web services or internet-based data exchanges.
Mitigation strategies for CVE-2019-2766 should prioritize immediate patching of affected Java installations, particularly focusing on the specific version numbers mentioned in the vulnerability description. Organizations should implement network segmentation and access controls to limit exposure of Java applications to untrusted networks, while also reviewing and updating their Java deployment policies to reduce reliance on potentially vulnerable sandboxed environments. Security teams should conduct comprehensive vulnerability assessments to identify all Java applications and systems that may be at risk, particularly those running older Java versions or those that continue to support applet-based functionality. The remediation process should include disabling Java applets in web browsers, implementing strict content filtering for Java-based web services, and monitoring network traffic for suspicious Java-related activity. Additionally, organizations should consider transitioning away from Java-based solutions where possible, as the vulnerability landscape for Java continues to evolve and new exploits are regularly discovered. This vulnerability aligns with CWE-284 (Improper Access Control) and can be mapped to ATT&CK techniques involving privilege escalation and credential access through application exploitation.