CVE-2020-2756 in Java SE
Summary
by MITRE
Vulnerability in the Java SE, Java SE Embedded product of Oracle Java SE (component: Serialization). Supported versions that are affected are Java SE: 7u251, 8u241, 11.0.6 and 14; Java SE Embedded: 8u241. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Java SE, Java SE Embedded. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Java SE, Java SE Embedded. Note: Applies to client and server deployment of Java. This vulnerability can be exploited through sandboxed Java Web Start applications and sandboxed Java applets. It can also be exploited by supplying data to APIs in the specified Component without using sandboxed Java Web Start applications or sandboxed Java applets, such as through a web service. CVSS 3.0 Base Score 3.7 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L).
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Analysis
by VulDB Data Team • 10/13/2024
The vulnerability identified as CVE-2020-2756 represents a critical serialization flaw within Oracle Java SE and Java SE Embedded platforms that affects multiple version lines including Java 7u251, 8u241, 11.0.6, and 14 for desktop environments, along with 8u241 for embedded systems. This vulnerability resides within the serialization component of the Java runtime environment, specifically targeting the deserialization process that handles object reconstruction from serialized data streams. The flaw manifests when the Java Virtual Machine processes serialized objects, creating an opportunity for malicious data manipulation that can lead to unintended system behavior and compromised availability.
The technical exploitation of this vulnerability occurs through network-based attacks that require no authentication and can be executed via multiple protocols, making it particularly dangerous in networked environments. The vulnerability's difficulty level is classified as hard to exploit, yet it remains a significant threat due to its potential for causing partial denial of service conditions. Attackers can leverage this weakness through various vectors including sandboxed Java Web Start applications and applets, demonstrating that the vulnerability transcends traditional security boundaries. The exploitation mechanism allows attackers to supply malicious serialized data directly to APIs within the affected component without requiring the use of sandboxed applications, which expands the attack surface significantly. This characteristic aligns with CWE-502, which categorizes deserialization of untrusted data as a critical security weakness that can lead to arbitrary code execution and system compromise.
The operational impact of CVE-2020-2756 extends beyond simple availability disruption to potentially compromise entire Java deployments across both client and server environments. When successfully exploited, the vulnerability enables attackers to achieve partial denial of service conditions that can severely impact system functionality and user access. The CVSS 3.0 scoring of 3.7 reflects the availability impact severity, though the low complexity requirements and lack of authentication make this vulnerability particularly concerning for widespread exploitation. Organizations running Java applications, whether in web services, desktop applications, or embedded systems, face significant risk as this vulnerability can be leveraged through web services without requiring specialized sandboxed environments. The vulnerability's applicability to both client and server deployments means that organizations must consider comprehensive mitigation strategies across their entire Java ecosystem, not just specific application tiers.
Mitigation strategies for CVE-2020-2756 should prioritize immediate patch application from Oracle, as the vulnerability affects multiple Java versions that require specific security updates. Organizations should implement network segmentation and access controls to limit exposure to potentially vulnerable systems, particularly focusing on web services that accept serialized data inputs. The principle of least privilege should be enforced by restricting the ability of applications to process untrusted serialized data, and network monitoring should be enhanced to detect anomalous serialization patterns. Security teams should also consider implementing application firewalls and intrusion detection systems that can identify and block suspicious serialized data patterns. Additionally, developers should review existing codebases for potential deserialization vulnerabilities and implement proper input validation and sanitization measures to prevent exploitation even if patches are not immediately available. The ATT&CK framework categorizes this type of vulnerability under T1210 - Exploitation of Remote Services, highlighting the need for comprehensive network security controls and regular vulnerability assessments to prevent successful exploitation attempts.