CVE-2018-17169 in PrinterOn
Summary
by MITRE
An XML external entity (XXE) vulnerability in PrinterOn version 4.1.4 and lower allows remote authenticated users to read arbitrary files or conduct server-side request forgery (SSRF) attacks via a crafted DTD in an XML request.
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Analysis
by VulDB Data Team • 09/06/2023
The vulnerability identified as CVE-2018-17169 represents a critical XML external entity flaw affecting PrinterOn version 4.1.4 and earlier releases. This vulnerability resides within the application's XML processing functionality, specifically in how it handles external entity declarations within XML documents. The flaw enables authenticated attackers to exploit the system's XML parser by crafting malicious XML requests containing specially designed Document Type Definitions. The vulnerability is classified under CWE-611 as an Improper Restriction of XML External Entity Reference, which directly maps to the core issue of uncontrolled external entity resolution. The attack vector requires an authenticated user context, meaning that adversaries must first establish valid credentials before exploiting the vulnerability, though this authentication requirement does not significantly mitigate the potential impact of the flaw.
The technical implementation of this vulnerability occurs when the PrinterOn application processes XML requests without proper validation or sanitization of external entity references. When a malicious DTD is included in an XML payload, the system's XML parser attempts to resolve external entities, which can lead to unauthorized file access or server-side request forgery operations. The vulnerability creates a pathway for attackers to bypass normal access controls and potentially extract sensitive data from the server's file system or redirect requests to internal services that should remain isolated. This type of attack can be particularly dangerous in enterprise environments where the printer management system may have access to internal network resources or sensitive corporate data. The flaw operates at the application layer and can be categorized under the ATT&CK technique T1071.004 for Application Layer Protocol: XML External Entity Injection.
The operational impact of CVE-2018-17169 extends beyond simple data exfiltration, as it can enable attackers to perform reconnaissance activities against internal systems and potentially escalate privileges within the network. An attacker could leverage the SSRF capability to probe internal services, access internal APIs, or even redirect requests to other vulnerable systems within the network perimeter. The file reading capability allows for extraction of configuration files, database credentials, or other sensitive information that might be stored in accessible locations on the server. Organizations running affected PrinterOn versions face significant risk of data breaches, compliance violations, and potential system compromise. The vulnerability's impact is particularly concerning given that many printer management systems serve as critical infrastructure components within enterprise environments, often requiring elevated privileges and having access to sensitive operational data.
Mitigation strategies for this vulnerability should focus on implementing proper XML parser configuration and input validation measures. Organizations should immediately upgrade to PrinterOn version 4.1.5 or later, which contains the necessary patches to address the XXE vulnerability. Additionally, administrators should implement strict XML parser settings that disable external entity resolution and DTD processing entirely. Network segmentation and access control measures can help limit the potential damage from exploitation, while monitoring systems should be configured to detect unusual XML processing activities. The implementation of web application firewalls and security scanning tools can provide additional layers of protection against such attacks. Security teams should also conduct comprehensive vulnerability assessments to identify other potential XXE vulnerabilities within their infrastructure and ensure that all XML processing components follow secure coding practices and adhere to industry standards such as those outlined in the OWASP XML External Entity Prevention Cheat Sheet.