Source: cve-assign@fb.com
react-dev-utils on Windows allows developers to run a local webserver for accepting various commands, including a command to launch an editor. The input to that command was not properly sanitized, allowing an attacker who can make a network request to the server (either via CSRF or by direct request) to execute arbitrary commands on the targeted system. This issue affects multiple branches: 1.x.x prior to 1.0.4, 2.x.x prior to 2.0.2, 3.x.x prior to 3.1.2, 4.x.x prior to 4.2.2, and 5.x.x prior to 5.0.2.
CVE-2018-6342 exposes a critical vulnerability in react-dev-utils on Windows, allowing attackers to achieve remote code execution (RCE). By exploiting a lack of input sanitization, attackers can send malicious commands to a local webserver, leading to arbitrary command execution on the targeted system and potential system compromise. This vulnerability poses a significant risk due to its ease of exploitation and potential for widespread impact.
Step 1: Target Identification: The attacker identifies a vulnerable system running a development environment that utilizes react-dev-utils and exposes the local webserver.
Step 2: Payload Crafting: The attacker crafts a malicious command, designed to execute arbitrary code on the target system. This command is typically formatted to leverage the webserver's command execution functionality.
Step 3: Request Delivery: The attacker sends a specially crafted network request (e.g., via CSRF or direct request) to the vulnerable webserver. This request contains the malicious command as input.
Step 4: Command Execution: The webserver, due to the lack of input sanitization, processes the attacker's command and executes it on the target system. This allows the attacker to execute arbitrary commands with the privileges of the webserver process.
Step 5: System Compromise (Potential): Depending on the executed command, the attacker can achieve various objectives, including data exfiltration, malware installation, or complete system compromise.
The vulnerability stems from insufficient input validation within the react-dev-utils package, specifically in the handling of commands received by the local webserver. The webserver, designed to facilitate development tasks, accepts commands, including one to launch an editor. The flaw lies in the lack of proper sanitization of the input provided to this command. An attacker can craft a malicious request containing arbitrary commands, which the server then executes without proper filtering or escaping. This allows for the execution of attacker-controlled commands on the victim's machine. The root cause is a command injection vulnerability due to the insecure handling of user-supplied data in the context of a webserver process. The absence of input validation allows for the injection of malicious commands that are then executed by the operating system.
While no specific APTs are definitively linked to this CVE, the nature of the vulnerability makes it attractive to various threat actors. It is a low-hanging fruit for attackers seeking initial access or privilege escalation. The potential for RCE makes it a valuable tool for attackers. The vulnerability is not currently listed on the CISA KEV list, but it's important to note the potential for exploitation if vulnerable systems are present.
Network traffic analysis: Look for unusual HTTP requests to the local webserver, especially those containing suspicious command-line arguments or payloads.
Process monitoring: Monitor for the execution of unexpected processes or commands initiated by the webserver process.
File integrity monitoring: Detect changes to critical system files or the creation of new malicious files.
Log analysis: Review webserver logs for suspicious activity, such as unusual request patterns or error messages related to command execution.
Endpoint Detection and Response (EDR) solutions: EDR tools can detect and alert on suspicious process executions and network connections.
Upgrade react-dev-utils to a patched version: 1.0.4+, 2.0.2+, 3.1.2+, 4.2.2+, or 5.0.2+.
Implement input validation and sanitization: Ensure that all user-supplied input is properly validated and sanitized before being used in commands.
Restrict access to the local webserver: Limit access to the webserver to only trusted users or networks.
Apply the principle of least privilege: Run the webserver with the minimum necessary privileges.
Regularly update dependencies: Keep all project dependencies up-to-date to patch known vulnerabilities.
Implement a Web Application Firewall (WAF): A WAF can help to filter malicious requests and prevent command injection attacks.