CVE-2021-20877 in Laser Printer
Summary
by MITRE • 02/08/2022
Cross-site scripting vulnerability in Canon laser printers and small office multifunctional printers (LBP162L/LBP162, MF4890dw, MF269dw/MF265dw/MF264dw/MF262dw, MF249dw/MF245dw/MF244dw/MF242dw/MF232w, and MF229dw/MF224dw/MF222dw sold in Japan, imageCLASS MF Series (MF113W/MF212W/MF217W/MF227DW/MF229DW, MF232W/MF244DW/MF247DW/MF249DW, MF264DW/MF267DW/MF269DW/MF269DW VP, and MF4570DN/MF4570DW/MF4770N/MF4880DW/MF4890DW) and imageCLASS LBP Series (LBP113W/LBP151DW/LBP162DW ) sold in the US, and iSENSYS (LBP162DW, LBP113W, LBP151DW, MF269dw, MF267dw, MF264dw, MF113w, MF249dw, MF247dw, MF244dw, MF237w, MF232w, MF229dw, MF217w, MF212w, MF4780w, and MF4890dw) and imageRUNNER (2206IF, 2204N, and 2204F) sold in Europe) allows remote attackers to inject an arbitrary script via unspecified vectors.
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Analysis
by VulDB Data Team • 02/12/2022
This cross-site scripting vulnerability affects a wide range of Canon multifunctional printers and laser printers sold across multiple geographic regions including Japan, the United States, and Europe. The vulnerability exists within the web interface of these devices, which serves as a primary attack vector for remote exploitation. The affected models span several product lines including LBP series, imageCLASS series, and imageRUNNER series, indicating a systemic issue within Canon's web server implementations across their printer portfolio. The vulnerability is classified as CWE-79 - Improper Neutralization of Input During Web Page Generation, which represents one of the most common and dangerous web application security flaws.
The technical flaw stems from insufficient input validation and output encoding within the printer's web interface components. Attackers can exploit this vulnerability through unspecified vectors that likely involve manipulating parameters passed to the web server running on the printer. These printers typically expose web interfaces for configuration management, status monitoring, and administrative functions, making them attractive targets for attackers seeking persistent access to networked environments. The vulnerability allows remote attackers to inject malicious scripts that can execute in the context of other users who access the printer's web interface, potentially leading to session hijacking, data theft, or further network compromise.
The operational impact of this vulnerability extends beyond simple script injection, as these devices often serve as networked endpoints that may be accessible from multiple network segments. When exploited, the XSS vulnerability can enable attackers to steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. Given that many of these printers are deployed in business environments, the potential for lateral movement within networks increases significantly. The vulnerability affects devices sold in Japan, US, and Europe, suggesting a widespread deployment across enterprise and small office environments, where these printers may have elevated privileges or access to sensitive network resources.
Mitigation strategies should focus on network segmentation and access controls to limit exposure of these devices to untrusted networks. Organizations should implement strict firewall rules that restrict access to printer web interfaces to authorized administrative users only, and consider disabling web interfaces entirely if not required for operations. Regular firmware updates from Canon should be deployed immediately upon availability, as the vendor likely released patches addressing this specific vulnerability. Network monitoring should include detection of unusual traffic patterns or attempts to access printer interfaces from unexpected locations. Additionally, implementing web application firewalls or proxy solutions for printer web interfaces can provide additional layers of protection against XSS attacks. The vulnerability's classification under CWE-79 emphasizes the need for comprehensive input sanitization and output encoding practices throughout the application stack, which should be enforced through regular security assessments and code reviews of embedded web components in networked devices.