A recent security vulnerability affecting Zyxel DX5401-B firmware has come to light, indicating a significant risk to sensitive information being exposed to attackers. This article will discuss the CVE-2023-28770 vulnerability in detail, guiding you through the ins and outs of the security issue, as well as providing a code snippet illustrating the vulnerability, links to original references, and exploit details. The aim is to create a comprehensive understanding of the issue and raise awareness about how such exploits occur.
Vulnerability Description
The sensitive information exposure vulnerability (CVE-2023-28770) in the CGI “Export_Log” and the binary “zcmd” in Zyxel DX5401-B firmware versions prior to V5.17(ABYO.1)C could allow a remote unauthenticated attacker to read the system files and to retrieve the password of the supervisor from the encrypted file. This means that an attacker does not need any privileged access to the network to exploit this vulnerability, which makes it a dangerous threat to any organization using the affected firmware.
The vulnerability exists in the following CGI component, which is the “Export_Log” file
/cgi-bin/Export_Log
By sending a crafted HTTP request to the vulnerable firmware device, an attacker can exploit this vulnerability and retrieve sensitive system information. The HTTP request should look like:
GET /cgi-bin/Export_Log?file=/path/to/sensitive/file HTTP/1.1
Host: target_device_ip
Connection: close
The attacker can replace "/path/to/sensitive/file" with the desired system file path such as the supervisor password file.
Zyxel has released an official security advisory which can be found at the following link
- Zyxel Security Advisory
Additionally, the National Vulnerability Database (NVD) has published a detailed entry regarding CVE-2023-28770, which can be accessed at this link:
- NVD - CVE-2023-28770
Exploit Details
The severity of this vulnerability cannot be underestimated. An attacker could leverage the vulnerability to retrieve sensitive information, including the supervisor password, which can lead to full network compromise as the supervisor has the highest level of access within the system.
To exploit this vulnerability, an attacker simply sends a specially crafted HTTP request to the vulnerable device, specifying the desired file to be read. There is no need for any other form of authentication or access, making this a "low-hanging fruit" for any potential attacker.
Recommendations
Zyxel has released a firmware upgrade that addresses this vulnerability. It is highly recommended that all affected users immediately upgrade to the latest firmware version (V5.17(ABYO.1)C) to protect their systems from potential exploitation. Delaying this upgrade could expose your organization to significant risks.
Conclusion
CVE-2023-28770 is a prime example of how seemingly simple vulnerabilities in firmware can have devastating impacts on the security of sensitive information. By staying informed on the latest security vulnerabilities and applying the necessary patches, organizations can work together to prevent unauthorized access to their systems and ensure that their sensitive data stays protected.
Timeline
Published on: 04/27/2023 09:15:00 UTC
Last modified on: 05/10/2023 18:15:00 UTC