CVE-2018-20767 in WorkCentre
Summary
by MITRE
An issue was discovered on Xerox WorkCentre 3655, 3655i, 58XX, 58XXi, 59XX, 59XXi, 6655, 6655i, 72XX, 72XXi, 78XX, 78XXi, 7970, 7970i, EC7836, and EC7856 devices before R18-05 073.xxx.0487.15000. There is authenticated remote command execution.
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Analysis
by VulDB Data Team • 05/29/2020
This vulnerability represents a critical authenticated remote command execution flaw affecting multiple Xerox WorkCentre multifunction printer models including the 3655, 58XX, 59XX, 6655, 72XX, 78XX, 7970, EC7836, and EC7856 series. The issue exists in firmware versions prior to R18-05 073.xxx.0487.15000, indicating a widespread problem across several generations of these devices. The vulnerability allows an authenticated attacker to execute arbitrary commands on the affected devices, potentially leading to complete system compromise and unauthorized access to sensitive information. This flaw falls under the CWE-78 weakness category, specifically related to command injection vulnerabilities where user-supplied input is not properly sanitized before being passed to system commands. The attack vector requires authentication, meaning that an attacker must first obtain valid credentials to exploit this vulnerability, though this does not significantly reduce the risk given that many organizations may have weak credential management practices.
The operational impact of this vulnerability is substantial as multifunction printers serve as critical components in enterprise networks, often acting as gateways between internal systems and external networks. These devices frequently process sensitive documents and may contain confidential data from various departments including human resources, finance, and legal services. When compromised, these devices can provide attackers with persistent access points within the network, enabling them to conduct reconnaissance activities, establish backdoors, or use the devices as launching platforms for further attacks. The vulnerability aligns with several ATT&CK techniques including T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as attackers can leverage legitimate administrative accounts to execute malicious commands. The presence of this vulnerability in devices from multiple product lines suggests a systemic design flaw that may be present across the entire Xerox WorkCentre product family.
The technical nature of this vulnerability stems from inadequate input validation and sanitization within the device's web interface or network services. Attackers can craft malicious payloads that, when processed by the device, result in unintended command execution. This typically occurs when user input is directly incorporated into system commands without proper filtering or escaping mechanisms. The affected devices likely use a combination of web technologies and embedded operating systems that process HTTP requests containing potentially malicious parameters. Organizations should consider implementing network segmentation to isolate these devices from critical systems and establish strict access controls. Regular firmware updates and patch management procedures are essential, though the vulnerability affects devices with relatively recent firmware versions, indicating that the issue may persist in widely deployed systems. The vulnerability also highlights the importance of securing Internet-facing devices and implementing robust network monitoring to detect anomalous command execution patterns. Organizations should also consider disabling unnecessary services and implementing strong authentication mechanisms including multi-factor authentication to reduce the attack surface. Given that these devices often operate in environments where physical access is possible, additional measures such as disabling unused network interfaces and implementing secure configuration baselines are recommended to minimize potential exploitation opportunities.