CVE-2018-18838 in Netdata
Summary
by MITRE
An issue was discovered in Netdata 1.10.0. Log Injection (or Log Forgery) exists via a %0a sequence in the url parameter to api/v1/registry.
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Analysis
by VulDB Data Team • 02/03/2025
The vulnerability identified as CVE-2018-18838 represents a significant security flaw in Netdata version 1.10.0 that exposes the system to log injection attacks. This issue resides within the api/v1/registry endpoint where the application fails to properly sanitize user input, specifically the url parameter that accepts %0a sequences. The %0a character represents a newline character in URL encoding, which when improperly handled can allow attackers to manipulate log files and potentially inject malicious content into the system's logging infrastructure. This vulnerability directly impacts the integrity and reliability of system logs that are critical for security monitoring and incident response operations.
The technical implementation of this flaw stems from inadequate input validation and sanitization practices within the Netdata registry API component. When a malicious user submits a crafted url parameter containing %0a sequences, the application processes this input without proper encoding or filtering mechanisms. This allows the newline character to be interpreted by the logging system, potentially causing log entries to be split or manipulated in unintended ways. The vulnerability operates at the application layer and can be exploited through web-based interactions with the Netdata API, making it particularly dangerous as it can be triggered remotely without requiring authentication or elevated privileges.
The operational impact of CVE-2018-18838 extends beyond simple log manipulation and can enable more sophisticated attack vectors. Attackers can leverage this vulnerability to forge log entries, potentially creating false security alerts or obscuring legitimate security incidents. The injected content may contain malicious payloads that could be executed by log analysis tools or forwarded to security information and event management systems. Additionally, this vulnerability can compromise the audit trail functionality of Netdata, making it difficult for security teams to accurately monitor system activities and detect genuine threats. The issue aligns with CWE-117, which specifically addresses improper output neutralization for logs, and can be classified under the ATT&CK technique T1070.101 for Indicator Removal on Host.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and sanitization measures within the Netdata application. The primary fix involves modifying the api/v1/registry endpoint to properly encode or reject newline characters and other potentially dangerous sequences in user-provided input. Organizations should also implement proper log parsing and monitoring mechanisms that can detect anomalous log entries that may indicate injection attempts. Regular updates to Netdata installations are essential to ensure that this and similar vulnerabilities are addressed through official patches. Security teams should also consider implementing network-level monitoring to detect unusual API access patterns that may indicate exploitation attempts. The remediation process should include thorough testing of input validation mechanisms to ensure that legitimate functionality is preserved while eliminating the security gap that allows log injection attacks to succeed.