CVE-2017-1000477 in XMLBundle
Summary
by MITRE
XMLBundle version 0.1.7 is vulnerable to XXE attacks which can result in denial of service attacks.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2017-1000477 affects XMLBundle version 0.1.7 and represents a critical security flaw that exposes systems to XML External Entity processing attacks. This vulnerability falls under the broader category of insecure deserialization and improper input validation issues that have plagued software systems for decades. The XMLBundle library, which is commonly used for handling XML data structures in various applications, fails to properly sanitize external entity references within XML documents, creating an exploitable condition that can be leveraged by malicious actors.
The technical implementation of this vulnerability stems from the library's failure to disable external entity resolution during XML parsing operations. When an application processes XML data through XMLBundle, it does not appropriately configure the XML parser to reject external entity declarations or references to external resources. This misconfiguration allows attackers to craft malicious XML payloads that reference external entities, potentially causing the parser to fetch remote resources or execute arbitrary code. The flaw specifically manifests when the library processes XML documents that contain external entity declarations, enabling attackers to exploit the system's XML parsing capabilities for unauthorized access or system compromise.
The operational impact of this vulnerability extends beyond simple denial of service conditions, though that represents the most immediate concern. While the primary effect may appear as a denial of service attack, the potential for more severe consequences exists, including information disclosure, server-side request forgery, and in some cases, remote code execution depending on the underlying system configuration. The vulnerability affects any application that utilizes XMLBundle version 0.1.7 for processing XML input, making it particularly dangerous in environments where user-supplied XML data is processed without proper validation or sanitization. Attackers can leverage this weakness to cause system resource exhaustion through recursive entity expansion, leading to service unavailability for legitimate users.
The vulnerability aligns with CWE-611, which specifically addresses improper restriction of XML external entity reference, and demonstrates characteristics consistent with ATT&CK technique T1213.002 related to data from information repositories. Organizations using affected versions of XMLBundle should immediately implement mitigations including disabling external entity resolution, implementing proper input validation, and restricting XML parser configurations to prevent unauthorized access to external resources. The recommended remediation strategy involves upgrading to a patched version of XMLBundle or implementing strict XML parsing configurations that explicitly disable external entity processing. Additionally, network-level controls such as firewalls and intrusion prevention systems can provide additional defense-in-depth measures to prevent exploitation attempts targeting this vulnerability.