What is CVE-2020-5902?
CVE-2020-5902 is a critical security vulnerability identified in the BIG-IP Traffic Management User Interface (TMUI), also referred to as the Configuration utility, of F5 Networks’ BIG-IP devices. This vulnerability allows remote attackers to execute arbitrary system commands, create or delete files, and disable services without authentication. It affects multiple versions of the BIG-IP products, posing a severe threat to organizations that rely on these devices for network traffic management and security.
CVSS Score and Severity
- CVSS Score: 10.0 (Critical)
- Severity: The CVSS score of 10.0 out of 10 reflects the critical nature of this vulnerability. The potential for remote code execution without authentication makes this a severe issue for organizations using F5 BIG-IP devices in their network infrastructure.
So what’s the problem?
CVE-2020-5902 is particularly dangerous because it allows attackers to take full control of the affected BIG-IP device remotely, enabling them to execute arbitrary commands, deploy malware, or disrupt services. Given that BIG-IP devices are often used to manage and secure high-value network traffic, a successful attack could lead to data breaches, operational downtime, and widespread compromise of an organization’s network.
Background and Context
Background on the vulnerability
CVE-2020-5902 was discovered in 2020 and affects the TMUI component of F5 Networks’ BIG-IP devices. The vulnerability arises from improper input handling in the TMUI, which fails to adequately sanitize user input in HTTP requests. This flaw allows attackers to send specially crafted requests that bypass authentication and execute arbitrary commands on the device. The vulnerability is particularly severe because it can be exploited remotely without any prior authentication.
Description of the Vulnerability (CVE-2020-5902)
The vulnerability occurs because the TMUI of the BIG-IP system does not properly sanitize input in certain HTTP requests. An attacker can craft a malicious request that includes arbitrary commands, which are executed on the device with root privileges. This can lead to complete system compromise, allowing the attacker to control the device, steal data, disable services, or deploy additional malicious payloads.
Root Cause Analysis
The root cause of CVE-2020-5902 is the lack of proper input validation and sanitization in the TMUI component of BIG-IP devices. The TMUI does not adequately filter or escape user-supplied input in HTTP requests, allowing attackers to inject and execute arbitrary commands. This issue is particularly concerning in environments where the TMUI is exposed to the internet or accessible by untrusted users.
Impact and Exploitation
The impact of CVE-2020-5902
Exploiting CVE-2020-5902 can have several severe impacts:
- Remote Code Execution: The most critical impact is the ability for an attacker to execute arbitrary commands on the device with root privileges, potentially leading to full control over the BIG-IP system.
- System Compromise: An attacker could use this vulnerability to manipulate system settings, disable critical services, or deploy malware, leading to a complete compromise of the device and the network it manages.
- Data Breach: The attacker could access sensitive data stored on the device or intercept network traffic, leading to data breaches and potential information theft.
Exploit
To exploit CVE-2020-5902, an attacker needs to send specially crafted HTTP requests to the vulnerable TMUI of a BIG-IP device. The exploitation process involves:
- Identifying a target BIG-IP device with the TMUI exposed to the internet.
- Crafting an HTTP request that includes malicious commands designed to exploit the input validation flaw.
- Sending the crafted request to the device, where it is processed, and the malicious commands are executed with root privileges, leading to the compromise of the device.
Proof of Concept (POC)
A basic Proof of Concept (POC) for CVE-2020-5902 might involve sending an HTTP GET request to the TMUI with a URL that includes a command injection payload. For example:
bash code
curl -k "https://<BIG-IP-IP>/tmui/login.jsp/..;/tmui/locallb/workspace/fileRead.jsp?fileName=/etc/passwd"This POC attempts to read the /etc/passwd file on the BIG-IP system by exploiting the directory traversal and command injection vulnerability. If successful, the response will include the contents of the /etc/passwd file, indicating that the system is vulnerable to this attack.
Note: This POC is for educational purposes only. Exploiting vulnerabilities without authorization is illegal and unethical.
Real-world Impact and Response
Timeline/changelog
- June 2020: Discovery of CVE-2020-5902 during a security review of F5 BIG-IP devices.
- July 2020: Public disclosure of the vulnerability and release of patches by F5 Networks to address the issue.
- July 2020: Security advisories and guidance issued to organizations to update their BIG-IP devices and secure their networks against potential exploitation.
- August 2020: Continued monitoring for potential exploitation and providing additional updates as needed.
Observed Activity
Since its disclosure, CVE-2020-5902 has been actively targeted by attackers, particularly in environments where BIG-IP devices are exposed to the internet. Exploitation has led to the compromise of network devices, the deployment of malware, and significant operational disruptions.
Mass Scanning
Following the disclosure of CVE-2020-5902, there has been a significant increase in scanning activity targeting F5 BIG-IP devices, particularly looking for systems with exposed TMUI interfaces. Attackers use automated tools to identify and exploit vulnerable devices.
Vulnerable Server Discovery
Vulnerable BIG-IP devices can be discovered by attackers through targeted scanning or by analyzing network traffic for signs of outdated versions. Ensuring that all devices are updated and properly configured is essential to prevent exploitation.
Reasoning and Scoring
Corporate networks impacted globally
CVE-2020-5902 has the potential to impact corporate networks globally, particularly in environments where F5 BIG-IP devices are used for critical network management and security functions. The vulnerability can be exploited to gain unauthorized access, execute arbitrary commands, and compromise the integrity of network devices.
Corporate numbers impacted by countries
- United States: Extensive use of F5 BIG-IP devices in enterprise and government environments, with many organizations potentially at risk.
- Europe: Significant adoption of F5 BIG-IP in finance, telecommunications, and critical infrastructure sectors, leading to potential exposure.
- Asia: Widespread use of F5 BIG-IP devices in industries where secure network management is critical.
Conclusion
Who should be paying attention to this?
System administrators, cybersecurity professionals, and organizations that use F5 BIG-IP devices for network management should prioritize attention to CVE-2020-5902. Ensuring that devices are updated and secure is critical for maintaining the integrity and confidentiality of network infrastructure.
Who is exploiting it and how?
CVE-2020-5902 has been actively exploited by attackers who identify vulnerable F5 BIG-IP devices with exposed TMUI interfaces. These attackers craft malicious HTTP requests designed to exploit the input validation flaw, leading to remote code execution and full control over the device.
How are things likely to develop?
As more organizations apply updates and secure their BIG-IP devices, 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-2020-5902 was discovered and disclosed in mid-2020, but the underlying issue with improper input validation may have existed in F5 BIG-IP devices for some time before its discovery. This highlights the importance of regular security reviews and updates to address potential vulnerabilities in critical network infrastructure.
