CVE-2018-8920 in DiskStation Manager
Summary
by MITRE
Improper neutralization of escape vulnerability in Log Exporter in Synology DiskStation Manager (DSM) before 6.1.6-15266 allows remote attackers to inject arbitrary content to have an unspecified impact by exporting an archive in CSV format.
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Analysis
by VulDB Data Team • 01/15/2025
The vulnerability identified as CVE-2018-8920 represents a critical improper neutralization of escape sequences flaw within the Log Exporter component of Synology DiskStation Manager (DSM) versions prior to 6.1.6-15266. This security weakness resides in the handling of log data export functionality when generating CSV formatted archives, creating a potential attack vector that could enable remote code execution or data manipulation. The vulnerability stems from insufficient input validation and sanitization mechanisms within the log export module, specifically when processing user-supplied data that gets embedded into the exported CSV files. Attackers can exploit this weakness by crafting malicious input that contains escape sequences designed to inject arbitrary content into the exported log files, potentially allowing them to manipulate the structure or content of the generated archives.
The technical implementation of this vulnerability involves the lack of proper sanitization of user-controllable data within the CSV export functionality of DSM's logging system. When users export log data in CSV format, the system fails to adequately escape special characters or validate the integrity of log entries before incorporating them into the exported file structure. This improper neutralization creates a condition where maliciously crafted log entries can contain escape sequences that alter the intended structure of the CSV output. The vulnerability is particularly concerning because CSV files are commonly used for data analysis and reporting purposes, making them valuable targets for attackers seeking to manipulate or compromise systems through data injection attacks. The flaw aligns with CWE-15 (Improper Neutralization of Special Elements) and represents a classic example of how inadequate input sanitization can lead to serious security implications.
The operational impact of CVE-2018-8920 extends beyond simple data corruption, as it can potentially enable attackers to execute arbitrary code or gain unauthorized access to sensitive system information. Remote attackers can leverage this vulnerability to inject malicious content into exported log files, which could then be processed by other systems or applications that consume these CSV files. This creates a potential chain of compromise where an attacker's malicious input could propagate through various system components, potentially leading to privilege escalation or complete system compromise. The vulnerability affects organizations using Synology DSM systems that have not updated to version 6.1.6-15266 or later, making it particularly dangerous in environments where log management and analysis are critical components of security monitoring. The attack surface is broad since log data is typically exported for security analysis, compliance reporting, and system monitoring purposes, making these files prime targets for manipulation.
Organizations should immediately implement mitigation strategies to address this vulnerability, beginning with the mandatory upgrade to Synology DSM version 6.1.6-15266 or later, which contains the necessary patches to prevent escape sequence injection in log exports. System administrators should also implement network segmentation and access controls to limit exposure of DSM systems to untrusted networks, reducing the attack surface for remote exploitation attempts. Additional defensive measures include implementing strict log file validation procedures for any CSV files imported or processed by automated systems, deploying network monitoring tools to detect anomalous log export activities, and establishing regular security audits of log management processes. The vulnerability demonstrates the importance of proper input validation and sanitization in security-critical components, aligning with ATT&CK technique T1070.004 (File Deletion) and T1059.001 (Command and Scripting Interpreter) as potential exploitation vectors. Organizations should also consider implementing security information and event management (SIEM) solutions that can detect and alert on suspicious patterns in log file exports, providing additional layers of protection against this and similar vulnerabilities.