CVE-2021-43774 in DocuCentre-VI C4471
Summary
by MITRE • 03/03/2022
A risky-algorithm issue was discovered on Fujifilm DocuCentre-VI C4471 1.8 devices. An attacker that obtained access to the administrative web interface of a printer (e.g., by using the default credentials) can download the address book file, which contains the list of users (domain users, FTP users, etc.) stored on the printer, together with their encrypted passwords. The passwords are protected by a weak cipher, such as ROT13, which requires minimal effort to instantly retrieve the original password, giving the attacker a list of valid domain or FTP usernames and passwords.
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Analysis
by VulDB Data Team • 03/06/2022
The vulnerability identified as CVE-2021-43774 represents a critical security flaw in Fujifilm DocuCentre-VI C4471 multifunction devices running firmware version 1.8. This issue stems from a weak cryptographic implementation that fundamentally undermines the security posture of the affected printers. The vulnerability exists within the device's address book functionality where user credentials are stored using a trivial encryption method that provides no real security protection. The flaw specifically affects the administrative web interface of the device, which can be accessed through default credentials, creating an initial attack vector that aligns with common misconfiguration patterns documented in the cybersecurity community. The presence of default credentials represents a well-known weakness that has been catalogued in various threat intelligence reports and security frameworks, including those referenced in the MITRE ATT&CK framework under initial access techniques.
The technical implementation of this vulnerability demonstrates a clear violation of cryptographic best practices and security standards. The use of ROT13 encryption for password storage constitutes a severe security flaw that directly maps to CWE-326 - Inadequate Encryption Strength and CWE-312 - Cleartext Storage of Sensitive Data. ROT13 is a simple character substitution cipher that provides zero security protection and can be reversed instantly without any computational effort, making it trivial for attackers to retrieve original passwords from the stored address book files. This weakness creates a situation where legitimate users' credentials are exposed in a manner that completely negates any security benefits that might have been intended through access controls. The vulnerability is particularly dangerous because it allows attackers to obtain a complete list of valid usernames and their corresponding passwords, enabling them to escalate privileges and move laterally within networks where these devices are deployed.
The operational impact of this vulnerability extends far beyond the immediate compromise of individual device credentials. When attackers obtain valid domain and FTP usernames and passwords through this vulnerability, they gain the ability to authenticate to network resources using legitimate credentials, potentially bypassing additional security controls and authentication mechanisms. This scenario represents a classic privilege escalation pathway that aligns with ATT&CK technique T1078 - Valid Accounts, where adversaries leverage legitimate credentials to gain access to systems and network resources. The vulnerability affects enterprise environments where multifunction printers serve as network endpoints, potentially providing attackers with access to sensitive network resources and creating opportunities for further compromise. The exposure of domain users' credentials could enable attackers to access shared resources, file servers, or other network services that rely on the same authentication mechanisms, creating cascading security implications throughout the organization's infrastructure.
Mitigation strategies for CVE-2021-43774 must address both the immediate vulnerability and broader security posture issues. Organizations should immediately disable or remove default administrative accounts and implement strong authentication controls for printer management interfaces. The most effective immediate remediation involves updating the device firmware to a version that addresses the weak encryption implementation, which represents a direct fix for the cryptographic weakness identified in the vulnerability. Network segmentation and access control measures should be implemented to limit access to printer management interfaces to authorized personnel only, reducing the attack surface and preventing unauthorized access to sensitive configuration data. Security monitoring should be enhanced to detect unusual access patterns to printer management interfaces, particularly when combined with credential access attempts. The vulnerability highlights the importance of proper cryptographic implementation in embedded systems and underscores the need for organizations to conduct regular security assessments of networked devices, including multifunction printers, which often operate with minimal security controls and can serve as entry points for broader network compromises.