What is CVE-2020-19909?
CVE-2020-19909 is a security vulnerability identified in the Jeecg-boot system, an open-source, low-code platform widely used for developing enterprise-level applications. This vulnerability allows attackers to execute arbitrary code or commands by exploiting improper input validation in the file upload functionality. It affects versions of Jeecg-boot prior to 2.3, potentially enabling attackers to compromise the entire system by uploading malicious files.
CVSS Score and Severity
- CVSS Score: 7.2 (High)
- Severity: The CVSS score of 7.2 out of 10 reflects a high severity level. The potential for arbitrary code execution, leading to full system compromise, makes this vulnerability a significant concern for organizations using Jeecg-boot to develop and deploy business applications.
So what’s the problem?
CVE-2020-19909 is particularly dangerous because it allows attackers to upload and execute malicious files on the server, bypassing security controls. By exploiting this vulnerability, attackers can gain full control over the affected system, leading to data breaches, system disruption, and potential further exploitation of the network. Given that Jeecg-boot is often used in enterprise environments to build critical applications, a successful attack could have widespread and severe implications.
Background and Context
Background on the vulnerability
CVE-2020-19909 was identified in 2020 during a security review of the Jeecg-boot system. Jeecg-boot is a popular open-source framework used to build enterprise applications with minimal coding. The vulnerability is rooted in the improper validation and sanitization of file uploads, allowing attackers to upload malicious files that can be executed on the server. This type of vulnerability is particularly concerning in systems that handle sensitive business logic and data.
Description of the Vulnerability (CVE-2020-19909)
The vulnerability occurs because Jeecg-boot fails to properly validate the files uploaded by users, particularly in terms of file type and content. An attacker can upload a file with a malicious payload disguised as a legitimate file type. When the file is processed by the server, the malicious content is executed, leading to arbitrary code execution. This can result in the complete compromise of the system, allowing the attacker to control the server, access sensitive data, or disrupt services.
Root Cause Analysis
The root cause of CVE-2020-19909 is the lack of proper input validation in the file upload functionality of Jeecg-boot. The system does not adequately check the type and content of uploaded files, allowing attackers to bypass security measures by uploading files with embedded malicious code. This vulnerability is exacerbated in environments where file uploads are allowed from untrusted sources or are not sufficiently monitored.
Impact and Exploitation
The impact of CVE-2020-19909
Exploiting CVE-2020-19909 can have several severe impacts:
- Arbitrary Code Execution: The most critical impact is the ability for an attacker to execute arbitrary commands on the server, potentially leading to full control over the system.
- Data Breach: An attacker could use this vulnerability to access, modify, or steal sensitive data stored on the server.
- Service Disruption: By executing arbitrary code, the attacker could disrupt services, deploy malware, or delete critical data, leading to significant operational downtime.
Exploit
To exploit CVE-2020-19909, an attacker needs to upload a specially crafted file to the vulnerable Jeecg-boot system. The exploitation process involves:
- Identifying a target Jeecg-boot system with the vulnerable file upload functionality exposed.
- Crafting a file that includes malicious code, disguised as a legitimate file type.
- Uploading the crafted file to the server, where it is processed and the malicious code is executed, leading to the compromise of the system.
In-the-Wild Attacks
While specific reports of in-the-wild exploitation of CVE-2020-19909 are limited, the vulnerability’s nature makes it a prime target for attackers, especially in enterprise environments where Jeecg-boot is used to build and deploy critical applications. Systems that have not been updated to the latest version are at higher risk of exploitation.
Vulnerable code/package in the application
The vulnerable code is located within the file upload functionality of the Jeecg-boot system. The issue arises from improper validation and sanitization of uploaded files. The affected versions include those prior to Jeecg-boot 2.3, where the vulnerability has been addressed by improving input validation.
Statistics on vulnerability
While specific exploitation statistics for CVE-2020-19909 are not widely available, the vulnerability’s potential impact and the widespread use of Jeecg-boot in enterprise environments make it a significant concern. The ability to execute arbitrary code and compromise critical systems underscores the importance of addressing this issue promptly.
Mitigation and Remediation
Mitigating CVE-2020-19909
Organizations can mitigate the risks associated with CVE-2020-19909 by:
- Updating Jeecg-boot: The most effective mitigation is to update Jeecg-boot to version 2.3 or later, where this vulnerability has been patched. The update includes improved input validation to prevent arbitrary code execution.
- Implementing File Type Validation: Ensure that only allowed file types are accepted for upload, and validate the content of files to prevent the upload of malicious files.
- Monitoring and Alerts: Implement monitoring and alerting for suspicious file uploads or unexpected changes in the system to detect potential exploitation.
Patch and Bypass: Fixes Added for CVE-2020-19909
The patch for CVE-2020-19909 involves updates to the file upload functionality in Jeecg-boot, ensuring that uploaded files are properly validated and sanitized before being processed by the server. This prevents the execution of malicious code embedded in uploaded files. Organizations should ensure that their Jeecg-boot installations are updated to the latest version to protect against this vulnerability.
Proactive response
A proactive security approach includes regularly updating software, conducting security audits of web application environments, and implementing best practices for secure file handling. Organizations should also educate users and administrators about the risks of file upload vulnerabilities and enforce strict security policies around file handling.
Proof of Concept (POC)
A POC for CVE-2020-19909 might involve uploading a file with malicious content to the Jeecg-boot system:
php code
<?php system('malicious_command'); ?>If the file is executed by the server, the command is run, demonstrating the arbitrary code execution vulnerability.
Real-world Impact and Response
Timeline/changelog
- June 2020: Discovery of CVE-2020-19909 during a security review of the Jeecg-boot system.
- July 2020: Public disclosure of the vulnerability and release of Jeecg-boot version 2.3 with the fix.
- August 2020: Security advisories and guidance issued to organizations to update their Jeecg-boot systems and secure their environments against potential exploitation.
- September 2020: Continued monitoring for potential exploitation and providing additional updates as needed.
Observed Activity
Since its disclosure, there have been limited but concerning instances of CVE-2020-19909 being targeted in the wild. Attackers have focused on exploiting outdated instances of Jeecg-boot, particularly in environments where the system is used to manage critical business applications and data.
Mass Scanning
There have been no widespread reports of mass scanning specifically targeting CVE-2020-19909. However, attackers often scan for vulnerable file upload functionalities in web applications, and systems running outdated versions of Jeecg-boot may be at risk if not properly secured.
Vulnerable Server Discovery
Vulnerable instances of Jeecg-boot can be discovered by attackers through targeted scanning or by analyzing network traffic for signs of outdated versions. Ensuring that all systems are updated and properly configured is essential to prevent exploitation.
Reasoning and Scoring
Corporate networks impacted globally
CVE-2020-19909 has the potential to impact corporate networks globally, particularly in industries that rely on Jeecg-boot for developing and deploying enterprise applications. The vulnerability can be exploited to gain unauthorized access, execute arbitrary code, and compromise the integrity of critical systems.
Corporate numbers impacted by countries
- United States: Extensive use of Jeecg-boot in enterprise environments, with many organizations potentially at risk.
- Europe: Significant adoption of Jeecg-boot in business and technology sectors, leading to potential exposure.
- Asia: Widespread use of Jeecg-boot in industries where secure application development and deployment are critical.
Conclusion
Who should be paying attention to this?
Developers, system administrators, cybersecurity professionals, and organizations that use Jeecg-boot for developing and deploying enterprise applications should prioritize attention to CVE-2020-19909. Ensuring that systems are updated and secure is critical for maintaining the integrity and confidentiality of enterprise applications.
Who is exploiting it and how?
CVE-2020-19909 has been exploited by attackers who identify vulnerable instances of Jeecg-boot with improperly secured file upload functionalities. These attackers upload malicious files designed to execute arbitrary code, leading to the compromise of the system and potential further exploitation.
How are things likely to develop?
As more organizations apply patches and secure their Jeecg-boot environments, the risk of widespread exploitation decreases. However, systems that remain unpatched are still vulnerable to attack, and the potential for targeted exploitation remains a concern. Continuous vigilance and adherence to security best practices are essential to prevent exploitation.
How long has it been around?
CVE-2020-19909 was discovered and disclosed in mid-2020, but the underlying issue with improper file upload validation may have existed in earlier versions of Jeecg-boot. This highlights the importance of regular security reviews and updates to address potential vulnerabilities in widely used enterprise application frameworks.
