CVE-2020-26945 in MyBatis
Summary
by MITRE • 10/11/2020
MyBatis before 3.5.6 mishandles deserialization of object streams.
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Analysis
by VulDB Data Team • 11/18/2020
The vulnerability identified as CVE-2020-26945 affects Apache MyBatis versions prior to 3.5.6 and represents a critical deserialization flaw that can lead to remote code execution. This vulnerability resides within MyBatis' object stream handling mechanisms, which are commonly used for data persistence operations in Java applications. The issue stems from insufficient validation during the deserialization process, creating an attack surface where maliciously crafted input can be exploited to execute arbitrary code on the target system. The vulnerability is particularly concerning because MyBatis is widely adopted in enterprise environments for database interaction, making it a prime target for attackers seeking to compromise applications.
The technical flaw manifests when MyBatis processes serialized object streams that contain malicious payloads. During deserialization, the framework fails to properly validate the incoming data structure, allowing attackers to inject serialized objects that contain malicious code. This vulnerability aligns with CWE-502, which specifically addresses deserialization of untrusted data, and represents a classic example of insecure deserialization where the application deserializes data without adequate safeguards. The flaw enables attackers to bypass normal security controls and execute arbitrary commands on the affected system, potentially leading to complete system compromise.
The operational impact of this vulnerability extends beyond simple code execution, as it can result in full system compromise, data exfiltration, and persistence mechanisms being established within the target environment. Attackers can leverage this vulnerability to gain unauthorized access to databases, escalate privileges, and move laterally within networks where MyBatis applications are deployed. The vulnerability affects applications using MyBatis for data persistence, particularly those that accept user input through serialized object streams or process external data that may contain serialized objects. Organizations running vulnerable versions of MyBatis are at significant risk, especially in environments where applications process untrusted data from external sources.
Mitigation strategies for CVE-2020-26945 primarily involve upgrading to MyBatis version 3.5.6 or later, which includes proper deserialization validation and safeguards. Security teams should also implement network segmentation and monitoring to detect unusual deserialization activities, while applying input validation controls to prevent malicious serialized objects from reaching the deserialization layer. Additional protective measures include disabling unnecessary deserialization capabilities, implementing strict access controls for database connections, and conducting regular security assessments of MyBatis implementations. The vulnerability demonstrates the importance of proper deserialization security practices and aligns with ATT&CK technique T1059.007 for execution through serialized objects, emphasizing the need for comprehensive security controls in application frameworks. Organizations should also consider implementing application whitelisting and runtime application self-protection mechanisms to further defend against similar vulnerabilities in the future.