CVE-2020-28490 in async-git
Summary
by MITRE • 02/18/2021
The package async-git before 1.13.2 are vulnerable to Command Injection via shell meta-characters (back-ticks). For example: git.reset('atouch HACKEDb')
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Analysis
by VulDB Data Team • 03/03/2021
The vulnerability identified as CVE-2020-28490 affects the async-git package versions prior to 1.13.2 and represents a critical command injection flaw that arises from improper input validation and sanitization. This vulnerability specifically manifests when the package processes user-provided arguments that contain shell meta-characters, particularly back-ticks which are used for command substitution in Unix-like systems. The flaw allows attackers to execute arbitrary commands on the system where the vulnerable package is installed, creating a significant security risk for applications that rely on this package for git operations.
The technical implementation of this vulnerability occurs within the git.reset function which accepts user input without proper sanitization or escaping of shell metacharacters. When an attacker provides input containing back-ticks such as 'atouch HACKEDb', the package processes this input directly in a shell context without adequate protection mechanisms. This allows the shell to interpret the back-tick characters as command substitution syntax, executing the commands contained within them. The vulnerability stems from a lack of proper input validation and shell escaping, which are fundamental security practices that should be implemented when dealing with user-provided data in shell contexts. This type of vulnerability is classified as CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and falls under the broader category of command injection attacks.
The operational impact of this vulnerability is severe and can result in complete system compromise when exploited by malicious actors. An attacker who can manipulate the git.reset function input can execute arbitrary commands with the privileges of the process running the vulnerable application. This could lead to data exfiltration, system modification, privilege escalation, or even full system takeover depending on the execution context. The vulnerability is particularly dangerous because it can be exploited through legitimate git operations, making it difficult to detect and prevent through traditional network monitoring. Applications using this package in environments with elevated privileges or those handling untrusted user input are at heightened risk of exploitation, as the vulnerability can be leveraged to perform unauthorized system operations.
Mitigation strategies for CVE-2020-28490 should focus on immediate remediation through package updates to version 1.13.2 or later, which contain proper input validation and sanitization mechanisms. Organizations should implement comprehensive input validation that rejects or escapes shell metacharacters before processing user-provided data. The implementation of secure coding practices including parameterized commands, proper shell escaping, and input sanitization should be enforced throughout the application. Additionally, system administrators should consider implementing principle of least privilege for applications using vulnerable packages, reducing the potential impact of successful exploitation. This vulnerability aligns with ATT&CK technique T1059.001 which covers command and scripting interpreter for execution, and T1021.004 which involves remote services for privilege escalation. Regular security audits and dependency checks should be conducted to identify and remediate similar vulnerabilities in other packages, ensuring comprehensive protection against command injection attacks that could compromise system integrity and confidentiality.