CVE-2016-1896 in Printer
Summary
by MITRE
Race condition in the initialization process on Lexmark printers with firmware ATL before ATL.02.049, CB before CB.02.049, PP before PP.02.049, and YK before YK.02.049 allows remote attackers to bypass authentication by leveraging incorrect detection of the security-jumper status.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/22/2018
The vulnerability identified as CVE-2016-1896 represents a critical race condition flaw in the initialization sequence of Lexmark printers running specific firmware versions. This security weakness affects multiple printer models and firmware variants including ATL before ATL.02.049, CB before CB.02.049, PP before PP.02.049, and YK before YK.02.049, creating a significant attack surface that remote adversaries can exploit to bypass authentication mechanisms. The flaw resides in how the printer firmware detects and processes the security-jumper status during the device initialization phase, where timing inconsistencies allow malicious actors to manipulate the authentication flow.
The technical implementation of this vulnerability stems from improper synchronization during the printer's boot process and security status evaluation. During initialization, the firmware performs checks to determine whether security features are enabled based on the physical security-jumper configuration. However, a race condition occurs when the system attempts to read the jumper status while other initialization processes are simultaneously executing, leading to inconsistent or incorrect detection of the security state. This timing discrepancy allows attackers to manipulate the sequence of operations and force the system into a state where authentication requirements are bypassed, effectively granting unauthorized access to printer functions and potentially sensitive data processing capabilities.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially compromise the entire printer security ecosystem. Remote exploitation means that attackers do not require physical access to the device, making this vulnerability particularly dangerous in networked environments where printers are often connected to corporate networks. The bypassed authentication could allow malicious actors to modify printer configurations, access stored print jobs, perform administrative functions, or potentially use the printer as a pivot point for further attacks within the network. This represents a significant risk to enterprise security infrastructure where printer devices often serve as entry points for broader network infiltration attempts.
Security professionals should consider this vulnerability in the context of the Common Weakness Enumeration classification as a race condition, specifically CWE-362, which deals with concurrent execution using improper synchronization. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under privilege escalation and initial access phases, where adversaries leverage system weaknesses to gain unauthorized access to network resources. Organizations should implement immediate mitigations including firmware updates to the affected Lexmark printer models, network segmentation to limit printer access, and monitoring for unusual authentication patterns or unauthorized configuration changes. Additionally, security teams should review their printer management policies and consider disabling unnecessary network services on printer devices to reduce the attack surface and prevent exploitation of similar timing-based vulnerabilities in other networked equipment.