CVE-2018-13284 in DiskStation Manager
Summary
by MITRE
Command injection vulnerability in ftpd in Synology Diskstation Manager (DSM) before 6.2-23739-1 allows remote authenticated users to execute arbitrary OS commands via the (1) MKD or (2) RMD command.
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Analysis
by VulDB Data Team • 01/15/2025
The vulnerability identified as CVE-2018-13284 represents a critical command injection flaw within the ftpd service component of Synology DiskStation Manager (DSM) versions prior to 6.2-23739-1. This issue affects the core FTP daemon implementation that handles file system operations through standard FTP commands. The vulnerability specifically manifests when processing two fundamental FTP commands: MKD (make directory) and RMD (remove directory). Attackers exploiting this flaw can manipulate the command execution flow by injecting malicious payloads into these commands, potentially compromising the entire storage system.
This command injection vulnerability falls under the CWE-77 category, specifically classified as "Improper Neutralization of Special Elements used in a Command ('Command Injection')". The flaw stems from inadequate input validation and sanitization within the ftpd service when processing user-supplied data through FTP protocol operations. The vulnerability exists because the system fails to properly escape or validate user input before incorporating it into system commands, allowing attackers to inject additional commands that execute with the privileges of the ftpd service process.
The operational impact of this vulnerability extends beyond simple command execution, as it provides authenticated attackers with significant control over the underlying operating system. Since the ftpd service typically runs with elevated privileges to manage file operations, successful exploitation could enable attackers to execute arbitrary system commands, potentially leading to complete system compromise. This includes the ability to modify system files, install malicious software, access sensitive data, or establish persistent backdoors. The remote authentication requirement means that attackers need valid credentials to exploit this vulnerability, but once compromised, the impact can be devastating to network security posture.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.001 (Command and Scripting Interpreter: PowerShell) and T1059.003 (Command and Scripting Interpreter: Windows Command Shell) as attackers can leverage the injected commands to perform various malicious activities. The attack surface is particularly concerning given that Synology DSM is widely deployed in enterprise environments, making this vulnerability attractive to threat actors seeking persistent access to network storage systems. The vulnerability also demonstrates the importance of proper input validation in network services, as the attack vector involves standard FTP protocol operations that are commonly used and exposed to external networks.
Organizations should implement immediate mitigations including updating to DSM version 6.2-23739-1 or later, which contains the necessary patches to address the command injection vulnerability. Network segmentation and access control measures should be enforced to limit FTP service exposure, particularly restricting access to trusted networks only. Additionally, monitoring should be implemented to detect suspicious FTP activity patterns that may indicate exploitation attempts. The vulnerability underscores the necessity of regular security updates and the importance of maintaining current firmware versions to protect against known exploits. Security teams should also conduct comprehensive vulnerability assessments to identify other potential command injection flaws within their network infrastructure and implement robust input validation controls across all network services.