CVE-2020-13124 in SABnzbd
Summary
by MITRE
SABnzbd 2.3.9 and 3.0.0Alpha2 has a command injection vulnerability in the web configuration interface that permits an authenticated user to execute arbitrary Python commands on the underlying operating system.
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Analysis
by VulDB Data Team • 11/08/2020
The vulnerability CVE-2020-13124 represents a critical command injection flaw within the SABnzbd software ecosystem, specifically affecting versions 2.3.9 and 3.0.0Alpha2. This issue resides within the web-based configuration interface of the software, which is designed to manage and configure the newsgroup downloader application. The vulnerability stems from improper input validation and sanitization within the web interface components that handle user-supplied parameters. An authenticated user can exploit this weakness by crafting malicious input that gets processed and executed as system commands, effectively allowing arbitrary code execution on the underlying operating system.
The technical implementation of this vulnerability aligns with CWE-77, which describes command injection flaws where user-supplied data is directly incorporated into system command execution without proper sanitization. The flaw occurs when the web interface fails to adequately validate or escape user inputs that are subsequently used in system command invocations. Attackers can leverage this vulnerability by manipulating configuration parameters through the web interface, potentially leading to complete system compromise. The authenticated nature of the exploit means that an attacker must first gain valid credentials to the SABnzbd web interface, but once authenticated, the impact extends beyond simple privilege escalation to full system control.
Operationally, this vulnerability poses significant risks to organizations that rely on SABnzbd for automated downloading and processing of content. The command injection allows attackers to execute arbitrary Python commands, which can lead to data exfiltration, system modification, or even complete system takeover. The impact extends beyond immediate local execution to potential lateral movement within network environments where SABnzbd might be deployed. Given that SABnzbd is commonly used in home and small office environments, this vulnerability can be particularly dangerous as it may provide attackers with persistent access to networks. The attack surface is further expanded by the fact that SABnzbd typically runs with elevated privileges to perform its downloading and processing functions, making successful exploitation potentially devastating.
Mitigation strategies for CVE-2020-13124 should prioritize immediate patching of affected versions to the latest stable releases where the vulnerability has been addressed. Organizations should implement network segmentation to limit access to the SABnzbd web interface and restrict authentication to trusted users only. Additional defensive measures include implementing web application firewalls to monitor and filter suspicious input patterns, enforcing strict input validation and sanitization at all interface points, and conducting regular security audits of web applications. The vulnerability also highlights the importance of following secure coding practices as outlined in the OWASP Top Ten and MITRE ATT&CK framework, particularly focusing on preventing command injection attacks through proper input handling and privilege separation. Regular security training for administrators and monitoring of system logs for anomalous command executions should also be implemented as part of comprehensive defense-in-depth strategies.