CVE-2019-17526 in Sage Cell Server
Summary
by MITRE
** DISPUTED ** An issue was discovered in SageMath Sage Cell Server through 2019-10-05. Python Code Injection can occur in the context of an internet facing web application. Malicious actors can execute arbitrary commands on the underlying operating system, as demonstrated by an __import__('os').popen('whoami').read() line. NOTE: the vendor's position is that the product is "vulnerable by design" and the current behavior will be retained.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability CVE-2019-17526 represents a critical code injection flaw in the SageMath Sage Cell Server, a web-based mathematical computation environment designed for educational and research purposes. This issue manifests as a Python code injection vulnerability that exists within the server's web interface, making it particularly dangerous when deployed in internet-facing environments where unauthorized access is possible. The vulnerability stems from insufficient input validation and sanitization mechanisms that allow malicious users to inject arbitrary Python code directly into the execution context of the server.
The technical exploitation of this vulnerability follows a well-documented pattern of code injection attacks where attackers leverage the server's permissive execution environment to bypass normal security boundaries. The specific demonstration of the vulnerability shows how an attacker can utilize the _import_('os').popen('whoami').read() construct to execute operating system commands directly through the Python interpreter. This attack vector demonstrates the severity of the flaw as it allows for complete system compromise, enabling attackers to execute arbitrary commands with the privileges of the web server process. The vulnerability operates at the application layer, specifically targeting the server's code execution capabilities and represents a classic example of a command injection vulnerability that can be classified under CWE-78 as improper neutralization of special elements used in OS commands.
From an operational perspective, the impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise and potential data exfiltration. Attackers who successfully exploit this vulnerability can gain unauthorized access to the underlying operating system, potentially leading to further lateral movement within network environments, data theft, or establishment of persistent backdoors. The fact that this vulnerability affects a mathematical computation server used in educational institutions and research environments creates additional risk as these systems often contain sensitive research data, intellectual property, or personal information. The vulnerability's presence in a web-facing application means that it can be exploited by remote attackers without requiring physical access to the system, making it particularly attractive to threat actors seeking automated exploitation opportunities.
The vendor's position that the product is "vulnerable by design" and that the current behavior will be retained represents a controversial stance that fundamentally undermines the security posture of the affected systems. This decision essentially acknowledges that the software's design intentionally allows for dangerous code execution capabilities to remain active, which aligns with certain security frameworks that recognize the need for explicit security controls. The vulnerability demonstrates how legitimate use cases for code execution in educational environments can create security risks when not properly isolated from external threats. Organizations using SageMath Sage Cell Server should consider implementing network segmentation, strict access controls, and monitoring solutions to detect potential exploitation attempts. The vulnerability also highlights the importance of proper input validation and the principle of least privilege in web application security, where the server should not execute arbitrary code without explicit user consent and proper sanitization. This case serves as a reminder of the inherent risks in allowing code execution in web environments and the necessity of implementing comprehensive security controls even in systems designed for legitimate educational purposes. The vulnerability's persistence despite known security risks represents a significant concern for organizations that rely on this software for mathematical computation and educational activities, as it creates a permanent attack surface that cannot be remediated through standard patching procedures.