CVE-2021-35560 in Java SE
Summary
by MITRE • 10/20/2021
Vulnerability in the Java SE product of Oracle Java SE (component: Deployment). The supported version that is affected is Java SE: 8u301. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Java SE. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in takeover of Java SE. Note: This vulnerability applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. This vulnerability does not apply to Java deployments, typically in servers, that load and run only trusted code (e.g., code installed by an administrator). CVSS 3.1 Base Score 7.5 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H).
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Analysis
by VulDB Data Team • 05/03/2025
This vulnerability resides within the Java SE deployment component of Oracle Java SE version 8u301, representing a significant security flaw that impacts the sandboxed execution environment of Java applications. The vulnerability operates at the core of Java's security model where untrusted code from remote sources is executed within restricted environments. The flaw specifically affects client-side deployments that utilize Java Web Start applications or applets, which are designed to run within sandboxed environments that typically provide strong isolation between the application and the underlying system. However, this particular vulnerability creates a pathway for attackers to bypass these security boundaries, potentially compromising the entire Java runtime environment.
The technical nature of this vulnerability involves a flaw in how Java handles certain code execution paths within its deployment framework, allowing for privilege escalation when untrusted code is loaded and executed. The vulnerability requires human interaction from users who must actively engage with the malicious content, typically through web browsing or application execution, making it a user-initiated attack vector. The attack surface is particularly concerning because it targets the fundamental security mechanisms that protect against malicious code execution in client environments where users expect robust sandboxing. This vulnerability demonstrates a critical weakness in Java's security architecture, specifically in how it validates and processes code that originates from untrusted sources, creating potential for complete system compromise.
The operational impact of this vulnerability is severe and multifaceted, as successful exploitation can lead to full takeover of the affected Java SE environment. The CVSS 3.1 score of 7.5 indicates high severity across all impact vectors, meaning attackers could achieve complete compromise of confidentiality, integrity, and availability of the targeted systems. The vulnerability's applicability extends primarily to client-side Java deployments where users execute code from the internet, such as in web browsers or Java Web Start applications. This makes it particularly dangerous in enterprise environments where employees regularly access internet-based applications and services. The attack requires network access and human interaction, but once initiated, the potential for lateral movement and system compromise is substantial, especially when considering that many organizations rely on Java applets and Web Start applications for legacy business processes.
Mitigation strategies for this vulnerability should focus on immediate deployment of Oracle's security patches and updates, particularly the Java SE 8u302 update which specifically addresses this flaw. Organizations should implement comprehensive network monitoring to detect suspicious Java-related activities and consider disabling Java applets and Web Start applications in browser environments where they are not strictly required. The principle of least privilege should be enforced by restricting Java execution to trusted environments only, and administrators should conduct thorough assessments of all Java-based applications and services to identify and eliminate unnecessary Java runtime dependencies. Additionally, implementing network segmentation and application whitelisting policies can significantly reduce the attack surface. This vulnerability aligns with CWE-248, which addresses "Uncaught Exception," and corresponds to ATT&CK techniques involving privilege escalation and code injection, emphasizing the need for layered defensive measures including endpoint protection, network firewalls, and user awareness training to prevent successful exploitation attempts.