Emerson Dixell XWEB-500 Arbitrary File Write Scanner

The Emerson Dixell XWEB-500 is utilized in refrigeration systems to manage, control, and monitor temperature and energy usage. Commonly, it is employed in commercial and industrial settings such as supermarkets, cold storage facilities, and food processing industries where maintaining specific environmental conditions is crucial. The product automates system processes, reduces energy consumption, and ensures optimal operation of refrigeration equipment. Generally handled by facility managers and service technicians, it is tasked with ensuring that temperature-sensitive products remain within safe parameters. Despite its critical role, the product has been unsupported since 2018, raising significant security concerns. Users continue to rely on it without awareness of potential vulnerabilities.

An Arbitrary File Write vulnerability allows attackers to write files to specific locations on a system. In Emerson Dixell XWEB-500, this vulnerability is present in CGI scripts such as /cgi-bin/logo_extra_upload.cgi, which lack authentication controls. The flaw permits an unauthorized user to specify files and their content to be written on the hosting system. Consequences include denial of service (DoS), data corruption, and increased risk of remote code execution (RCE), as malicious actors can overwrite critical system files. The severity is compounded by the lack of software updates since 2018, making systems using this product increasingly vulnerable over time. Organizations using this product should be aware of the significant risks involved.

The vulnerability stems from the improper handling of file upload requests in the CGI scripts of Emerson Dixell XWEB-500. These scripts, such as /cgi-bin/logo_extra_upload.cgi, allow attackers to send specially crafted requests without requiring authentication. The requests can include arbitrary data and file paths, effectively enabling the attacker to overwrite files on the device. For instance, POST requests to the affected endpoints can specify a payload that gets saved directly to the specified location. Matchers confirm the successful write operation by retrieving the crafted file. This vector is particularly dangerous as it allows for further exploitation, including the potential for executing arbitrary code on the compromised system.

The successful exploitation of this vulnerability can lead to severe consequences, including, but not limited to, denial of service. By overwriting critical system files, attackers can disrupt the normal functioning of the Emerson Dixell XWEB-500, rendering it inoperative. In more severe cases, the ability to write arbitrary files could allow attackers to execute malicious code remotely, leading to complete system compromise and unauthorized access to sensitive data. Additionally, continued use of outdated and unsupported systems increases the risk of exploitation, potentially resulting in financial loss, reputational damage, and regulatory penalties. Organizations must address this vulnerability to protect their systems and data.

REFERENCES

• https://www.exploit-db.com/exploits/50639
• https://nvd.nist.gov/vuln/detail/CVE-2021-45420