CVE-2018-18959 in WorkForce WF-2861
Summary
by MITRE
An issue was discovered on Epson WorkForce WF-2861 10.48 LQ22I3, 10.51.LQ20I6 and 10.52.LQ17IA devices. On the 'Air Print Setting' web page, if the data for 'Bonjour Service Location' at /PRESENTATION/BONJOUR is more than 251 bytes when sending data for Air Print Setting, then the device no longer functions until a reboot.
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Analysis
by VulDB Data Team • 04/24/2020
This vulnerability exists in Epson WorkForce WF-2861 series printers with firmware versions 10.48 LQ22I3, 10.51.LQ20I6, and 10.52.LQ17IA, representing a classic buffer overflow condition that affects the device's web interface handling of network service discovery parameters. The flaw manifests specifically within the Bonjour Service Location parameter processing on the Air Print Setting web page, where the device fails to properly validate input length before processing. When an attacker or legitimate user submits data exceeding 251 bytes for the Bonjour Service Location field at the /PRESENTATION/BONJOUR endpoint, the device experiences a critical failure that renders it non-functional until manual reboot is performed. This represents a denial of service vulnerability that can be exploited by any user with access to the device's web interface, making it particularly concerning for networked environments where printer availability is critical. The vulnerability stems from inadequate input validation and memory management within the web server component of the printer's firmware, which lacks proper bounds checking mechanisms to prevent buffer overflows. This issue aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers stack-based buffer overflow scenarios, though the specific implementation appears to involve heap corruption given the nature of web server memory handling. The impact extends beyond simple service disruption as it can affect business operations in office environments where these printers serve as essential network resources for document printing and scanning operations. The device's inability to function until reboot creates a persistent availability issue that can last for extended periods, potentially causing workflow interruptions and requiring administrative intervention to restore service.
The operational impact of this vulnerability extends significantly beyond the immediate denial of service condition, as it affects the printer's ability to maintain network connectivity and service discovery capabilities that are fundamental to modern office printing environments. Network administrators may find themselves unable to manage or configure the device through its web interface, potentially forcing reliance on physical console access or network-based management tools that may also be affected by the broader system instability. The vulnerability's exploitation requires minimal technical skill and can be achieved through simple web form submissions, making it particularly dangerous in unsecured network environments where unauthorized users might gain access to the printer's web management interface. This weakness creates opportunities for both accidental and intentional disruption of printing services, potentially affecting critical business processes that depend on reliable document output capabilities. The device's failure mode is particularly concerning as it does not simply return an error message or reject invalid input, but instead completely crashes the web server component, forcing the entire device to reboot. This behavior suggests a lack of proper error recovery mechanisms and indicates that the firmware does not implement graceful degradation when encountering malformed input data, which violates fundamental principles of robust system design. The vulnerability also has implications for network security posture as it could potentially be leveraged as a stepping stone for further attacks, particularly in environments where printers are not properly segmented from critical network infrastructure.
Mitigation strategies for this vulnerability should include immediate firmware updates from Epson to address the buffer overflow condition in the web server component, as well as network segmentation practices to limit access to printer management interfaces to authorized personnel only. Network administrators should implement access controls and authentication measures to prevent unauthorized modification of printer settings, particularly those affecting network service discovery parameters. The vulnerability can be mitigated through proper input validation at the network level using firewall rules that limit the size of data accepted by the printer's web interface, though this approach may impact legitimate use cases where larger Bonjour service locations are required. Organizations should also implement monitoring solutions that can detect unusual patterns in printer network traffic that might indicate exploitation attempts, particularly around the /PRESENTATION/BONJOUR endpoint. The recommended approach involves applying vendor-provided security patches that correct the input validation logic and implement proper bounds checking for all user-supplied data. Additionally, network administrators should consider disabling unnecessary services such as Air Print and Bonjour discovery if they are not required for business operations, thereby reducing the attack surface. This vulnerability demonstrates the importance of implementing defense-in-depth strategies that include both perimeter security controls and proper device configuration management to prevent exploitation of similar buffer overflow conditions in networked printing devices. The issue also highlights the need for regular security assessments of networked devices to identify and remediate vulnerabilities before they can be exploited by malicious actors, as outlined in the mitre ATT&CK framework's approach to identifying and mitigating device-level threats.