CVE-2020-21585 in emlog
Summary
by MITRE • 04/03/2021
Vulnerability in emlog v6.0.0 allows user to upload webshells via zip plugin module.
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Analysis
by VulDB Data Team • 04/08/2021
The vulnerability identified as CVE-2020-21585 represents a critical security flaw in emlog version 6.0.0 that enables unauthorized code execution through improper file validation mechanisms. This issue specifically affects the plugin module functionality within the content management system, creating an avenue for attackers to escalate privileges and gain persistent access to affected systems. The vulnerability stems from insufficient input sanitization and validation processes that fail to properly verify the contents of uploaded zip archives before processing them as plugin installations.
This security weakness operates through a path traversal and code execution vector that allows malicious actors to upload specially crafted zip files containing webshell components. When the system processes these archives, it extracts and executes the malicious code without adequate security checks, effectively bypassing the intended plugin installation restrictions. The vulnerability demonstrates a classic improper input validation issue that aligns with CWE-22 Path Traversal and CWE-434 Unrestricted Upload of File with Dangerous Type classifications. Attackers can leverage this flaw to deploy backdoors, steal sensitive data, or establish persistent command and control channels within the compromised environment.
The operational impact of this vulnerability extends beyond immediate code execution capabilities to encompass broader system compromise and data exfiltration risks. Once a webshell is successfully deployed, attackers can maintain long-term access to the compromised emlog installation, potentially escalating privileges to system-level access depending on the underlying server configuration. This vulnerability directly maps to ATT&CK technique T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as it enables adversaries to execute malicious commands through legitimate system interfaces while potentially leveraging compromised user credentials. The affected system may experience unauthorized access to sensitive user data, including personal information, login credentials, and potentially confidential business data stored within the emlog platform.
Organizations utilizing emlog version 6.0.0 should immediately implement comprehensive mitigation strategies including immediate patching of the software to the latest available version that addresses this vulnerability. Additional protective measures should encompass strict file type validation, implementation of secure upload restrictions, and enhanced monitoring of plugin installation activities. Network segmentation and access controls should be reinforced to limit potential lateral movement if exploitation occurs. Security teams must conduct thorough vulnerability assessments to identify any previously compromised systems and implement proper incident response procedures. The vulnerability also necessitates regular security audits of third-party plugins and modules to ensure continued compliance with security best practices, as this issue demonstrates the critical importance of validating all user-supplied content before system processing.