CVE-2011-3521 in JRE
Summary
by MITRE
Unspecified vulnerability in the Java Runtime Environment component in Oracle Java SE JDK and JRE, 7, 6 Update 27 and earlier, and 5.0 Update 31 and earlier allows remote untrusted Java Web Start applications and untrusted Java applets to affect confidentiality, integrity, and availability via unknown vectors related to Deserialization.
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Analysis
by VulDB Data Team • 11/24/2021
The vulnerability identified as CVE-2011-3521 represents a critical security flaw within the Java Runtime Environment component of Oracle Java SE JDK and JRE versions up to 7, 6 Update 27, and 5.0 Update 31. This weakness specifically affects the deserialization process within Java applications, creating potential attack vectors through untrusted Java Web Start applications and applets. The vulnerability operates at a fundamental level of the Java execution environment, where the deserialization mechanism fails to properly validate incoming data streams, potentially allowing malicious actors to exploit this gap for unauthorized system access. The unspecified nature of the exact attack vectors makes this vulnerability particularly dangerous as it could encompass multiple exploitation techniques across different application contexts.
The technical flaw stems from inadequate input validation during the deserialization phase of Java applications, which is a core functionality in the Java platform architecture. When Java applications receive serialized data streams from untrusted sources, the deserialization process should rigorously validate and sanitize this input before reconstructing objects from the serialized format. However, in affected versions, this validation mechanism is insufficient, allowing attackers to craft malicious serialized data that can execute arbitrary code when processed by the vulnerable Java runtime. This vulnerability directly relates to CWE-502 which classifies deserialization of untrusted data as a critical weakness in software security, where the improper handling of serialized objects can lead to remote code execution, data corruption, and system compromise.
The operational impact of CVE-2011-3521 extends across multiple security domains including confidentiality, integrity, and availability as indicated in the vulnerability description. Attackers exploiting this vulnerability can potentially gain unauthorized access to systems running vulnerable Java versions, enabling them to execute malicious code with the privileges of the Java application. This could lead to complete system compromise where attackers can establish persistent backdoors, exfiltrate sensitive data, modify system files, or disrupt service availability. The vulnerability affects both Java Web Start applications and applets, meaning that users can be compromised through web-based attacks, making the attack surface particularly wide. Organizations running legacy Java applications are especially vulnerable as these older versions are often not updated due to compatibility concerns or lack of proper patch management processes.
Mitigation strategies for CVE-2011-3521 should focus on immediate patching of affected Java installations to the latest available versions that contain fixes for the deserialization vulnerability. Organizations should implement network segmentation and firewall rules to restrict access to Java applets and Web Start applications where possible, particularly in environments where users have limited administrative privileges. The principle of least privilege should be enforced by configuring Java security settings to restrict applet execution and limiting the capabilities of untrusted code. Additionally, implementing application whitelisting solutions can prevent execution of unauthorized Java applications. Security monitoring should include detection of suspicious deserialization activities and network traffic patterns that may indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 which covers scripting languages and T1133 which addresses external remote services, indicating that exploitation may occur through web-based delivery mechanisms targeting the Java runtime environment. Organizations should also consider implementing network-based intrusion detection systems to identify potential exploitation attempts and establish incident response procedures specifically tailored to address Java-related security incidents.