CVE-2017-5645 in Identity Manager Connector
Summary
by MITRE
In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events from another application, a specially crafted binary payload can be sent that, when deserialized, can execute arbitrary code.
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Analysis
by VulDB Data Team • 07/29/2024
The vulnerability identified as CVE-2017-5645 represents a critical deserialization flaw within Apache Log4j 2.x versions prior to 2.8.2, specifically affecting the TCP and UDP socket server implementations. This vulnerability stems from the improper handling of serialized Java objects received through network connections, creating a pathway for remote code execution attacks. The flaw exists in the socket server components that are designed to receive log events from applications, making it particularly dangerous in environments where these servers are exposed to untrusted networks or external systems.
The technical implementation of this vulnerability involves the deserialization of binary payloads that are transmitted over TCP or UDP connections to the Log4j socket server. When the socket server receives these serialized objects, it attempts to deserialize them without proper validation or sanitization of the input data. This deserialization process can be manipulated by attackers who craft malicious binary payloads that contain serialized Java objects designed to execute arbitrary code upon deserialization. The vulnerability is classified under CWE-502 as Deserialization of Untrusted Data, which is a well-documented weakness in software security practices where applications fail to properly validate data before deserializing it.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass a broad range of potential security breaches. Attackers can leverage this vulnerability to gain complete control over systems running vulnerable Log4j versions, potentially leading to data exfiltration, system compromise, and lateral movement within network environments. The attack vector is particularly concerning because it requires minimal privileges to exploit and can be executed against systems that are otherwise properly secured. This vulnerability has been classified under the MITRE ATT&CK framework as part of the T1059.007 technique, which covers "Command and Scripting Interpreter: PowerShell" and similar execution methods that can be leveraged through deserialization attacks.
Organizations utilizing Apache Log4j 2.x socket servers are particularly at risk, especially those with these servers exposed to external networks or those that receive log data from untrusted sources. The vulnerability affects the SocketServer class in Log4j 2.x, which is commonly used in enterprise logging infrastructure where applications send structured log data to centralized servers for processing and analysis. The exploitation of this vulnerability can result in complete system compromise, making it one of the more severe issues in the Java ecosystem. The vulnerability's impact is amplified by the widespread adoption of Log4j across enterprise environments, making it a prime target for attackers seeking to exploit multiple systems simultaneously.
The recommended mitigation strategy involves upgrading to Apache Log4j 2.8.2 or later versions where this vulnerability has been addressed through proper input validation and sanitization of deserialized data. Additionally, organizations should implement network segmentation to restrict access to socket server endpoints, disable unnecessary socket server functionality, and consider implementing network monitoring to detect suspicious deserialization activity. The fix implemented in version 2.8.2 includes enhanced validation of serialized object data and improved handling of potentially malicious payloads during the deserialization process, aligning with security best practices for preventing deserialization attacks. Organizations should also conduct thorough vulnerability assessments to identify any systems running vulnerable versions of Log4j and ensure that all network-facing socket server components are properly secured.