CVE-2012-2656 in Restlet
Summary
by MITRE
An XML eXternal Entity (XXE) issue exists in Restlet 1.1.10 in an endpoint using XML transport, which lets a remote attacker obtain sensitive information.
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Analysis
by VulDB Data Team • 03/15/2024
The CVE-2012-2656 vulnerability represents a critical XML External Entity processing flaw within the Restlet framework version 1.1.10, specifically affecting applications that utilize XML transport mechanisms. This vulnerability falls under the CWE-611 weakness category, which encompasses issues related to improper restriction of XML external entities, making it a prime example of how XML parsing libraries can become attack vectors when not properly secured. The flaw manifests in RESTful web services that process XML data through the Restlet framework, creating an avenue for malicious actors to exploit the underlying XML parser's handling of external entities.
The technical implementation of this vulnerability stems from the Restlet framework's XML processing capabilities, where the application fails to properly sanitize or restrict external entity references during XML parsing operations. When a malicious XML document is submitted to an endpoint utilizing XML transport, the parser will attempt to resolve external entities referenced within the document, potentially leading to information disclosure through mechanisms such as file retrieval, network connections to internal services, or exposure of system resources. This issue is particularly dangerous because it allows remote attackers to leverage the XML parsing functionality to access sensitive data without requiring authentication or direct system access.
The operational impact of CVE-2012-2656 extends beyond simple information disclosure, as it can enable attackers to perform reconnaissance activities against internal systems, potentially leading to more severe exploitation opportunities. Attackers can craft malicious XML payloads that reference internal resources, causing the vulnerable application to inadvertently expose file system contents, internal network information, or other sensitive data that would normally be protected by network segmentation. This vulnerability particularly affects web services that process untrusted XML input from external sources, making it a significant concern for applications handling user-submitted data or integrating with external APIs that may provide XML-formatted responses.
Organizations should implement immediate mitigations including updating to patched versions of the Restlet framework, implementing proper XML parser configuration to disable external entity resolution, and employing input validation mechanisms that filter or sanitize XML content before processing. The vulnerability aligns with ATT&CK technique T1059.007 for XML external entity processing, and organizations should consider implementing network segmentation and monitoring for unusual XML parsing activities. Additional protective measures include deploying web application firewalls that can detect and block malicious XML payloads, implementing strict input validation policies, and conducting regular security assessments to identify other potential XXE vulnerabilities within the application stack. The remediation process should also involve comprehensive code reviews to ensure that XML parsing operations do not inadvertently expose system resources or internal network information through external entity references.