CVE-2020-8840 in jackson-databind
Summary
by MITRE
FasterXML jackson-databind 2.0.0 through 2.9.10.2 lacks certain xbean-reflect/JNDI blocking, as demonstrated by org.apache.xbean.propertyeditor.JndiConverter.
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Analysis
by VulDB Data Team • 02/25/2025
The vulnerability identified as CVE-2020-8840 affects the FasterXML jackson-databind library version 2.0.0 through 2.9.10.2, representing a critical security flaw that enables remote code execution through deserialization attacks. This issue stems from insufficient protection against JNDI (Java Naming and Directory Interface) lookups within the xbean-reflect component, specifically through the org.apache.xbean.propertyeditor.JndiConverter class. The vulnerability allows attackers to exploit the deserialization process to execute arbitrary code on systems running vulnerable versions of the library, making it a significant concern for applications that deserialize untrusted data.
The technical flaw resides in the lack of proper blocking mechanisms for JNDI lookups during object deserialization. When jackson-databind processes serialized data containing JNDI references, it fails to prevent the resolution of remote JNDI endpoints that could point to malicious servers. This occurs because the library does not implement adequate safeguards to detect or block potentially dangerous JNDI references in the deserialization chain. The org.apache.xbean.propertyeditor.JndiConverter class specifically handles JNDI lookups and lacks proper validation to prevent exploitation, creating a pathway for attackers to execute commands on the target system.
The operational impact of this vulnerability is severe and far-reaching, as it enables attackers to achieve remote code execution without requiring authentication or specific user interaction. Applications using vulnerable versions of jackson-databind that process untrusted input are at risk of being compromised, potentially leading to full system compromise, data exfiltration, or further lateral movement within network environments. The vulnerability affects a wide range of systems since jackson-databind is a widely used library for JSON processing in java applications, including web applications, microservices, and enterprise systems that handle JSON data from external sources.
Organizations should immediately upgrade to jackson-databind version 2.9.10.3 or later, which includes the necessary blocking mechanisms for xbean-reflect/JNDI lookups. Additional mitigations include implementing proper input validation and sanitization for all deserialization operations, using security frameworks like Spring Security or OWASP ESAPI to restrict deserialization, and employing application firewalls or intrusion detection systems to monitor for suspicious JNDI lookup patterns. Security teams should also consider implementing network segmentation and monitoring for outbound JNDI connections to detect potential exploitation attempts. This vulnerability aligns with CWE-502, which describes deserialization of untrusted data, and maps to ATT&CK technique T1059.007 for command and script interpreter, specifically the use of Java for remote code execution. Organizations must also review their application architectures to ensure that deserialization of untrusted data is minimized or completely avoided where possible, implementing the principle of least privilege for serialization operations.