CVE-2020-1956 in Kylin
Summary
by MITRE
Kylin has some restful apis which will concatenate os command with the user input string, a user is likely to be able to execute any os command without any protection or validation.
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2020-1956 affects Kylin, a data analysis platform that exposes RESTful APIs for various administrative and operational functions. This issue stems from improper input validation within the platform's API endpoints where user-supplied data is directly concatenated with operating system commands without adequate sanitization or validation mechanisms. The flaw represents a critical security weakness that allows malicious actors to inject arbitrary commands into the system through carefully crafted API requests.
This vulnerability manifests as a command injection flaw that aligns with CWE-77, which specifically addresses improper neutralization of special elements used in operating system commands. The technical implementation involves the platform's failure to properly escape or validate user input before incorporating it into system command executions. When legitimate API endpoints process user data, they construct command strings by directly concatenating user-supplied parameters with system command templates, creating an environment where attackers can manipulate the command execution flow.
The operational impact of this vulnerability is severe and multifaceted, potentially allowing attackers to execute arbitrary operating system commands with the privileges of the Kylin service account. This could lead to complete system compromise, data exfiltration, privilege escalation, and lateral movement within the network infrastructure. Attackers could leverage this vulnerability to install backdoors, modify system configurations, access sensitive data, or disrupt services. The attack surface extends beyond simple command execution to include potential privilege escalation scenarios where attackers might gain elevated system privileges through the compromised API endpoints.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1059.001 for command and scripting interpreter execution, and T1068 for exploit for privilege escalation. The attack chain typically involves an initial reconnaissance phase to identify vulnerable API endpoints, followed by crafting malicious payloads that exploit the command injection flaw. The lack of input validation creates an automated attack vector where attackers can potentially exploit this vulnerability at scale without requiring extensive manual intervention.
Mitigation strategies should focus on implementing proper input validation and sanitization mechanisms across all API endpoints that process user-supplied data. The recommended approach involves adopting parameterized command execution where user input is properly escaped or encoded before being used in system commands. Organizations should implement strict input validation using allowlists for acceptable characters and command patterns, while also employing principle of least privilege for the Kylin service account. Additionally, regular security code reviews and penetration testing should be conducted to identify and remediate similar vulnerabilities in other components of the system. Network segmentation and API gateway controls can provide additional layers of protection by limiting access to vulnerable endpoints and monitoring for suspicious API activity patterns.