CVE-2022-47514 in XML-RPC.NET
Summary
by MITRE • 12/18/2022
An XML external entity (XXE) injection vulnerability in XML-RPC.NET before 2.5.0 allows remote authenticated users to conduct server-side request forgery (SSRF) attacks, as demonstrated by a pingback.aspx POST request.
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Analysis
by VulDB Data Team • 01/14/2023
The CVE-2022-47514 vulnerability represents a critical XML external entity injection flaw within the XML-RPC.NET library prior to version 2.5.0, exposing systems to sophisticated server-side request forgery attacks. This vulnerability specifically manifests when the library processes XML-RPC requests containing malicious external entity declarations, allowing attackers to manipulate the underlying XML parser behavior. The flaw enables remote authenticated users to craft specially formatted requests that trigger unintended network communications from the vulnerable server, creating a pathway for unauthorized data exfiltration and system reconnaissance. The vulnerability is particularly concerning because it operates at the XML parsing layer where external entity resolution is permitted without proper validation, creating a fundamental security gap in the request processing pipeline.
The technical exploitation of this vulnerability occurs through the manipulation of XML-RPC requests that contain external entity references pointing to malicious resources. When the XML-RPC.NET library processes such requests, it fails to properly sanitize or disable external entity resolution, allowing the parser to fetch and process external resources. The specific demonstration involves a pingback.aspx POST request that leverages the XXE vulnerability to make outbound network requests from the target server. This behavior enables attackers to perform various malicious activities including internal network scanning, data exfiltration, and potentially access to internal services that would normally be isolated from external access. The vulnerability's impact is amplified by the fact that it requires only authentication to exploit, making it accessible to users with legitimate access credentials.
From an operational perspective, the vulnerability creates significant risks for organizations relying on XML-RPC.NET for web services integration and communication. The server-side request forgery capability allows attackers to bypass network segmentation and access internal systems that are not directly exposed to the internet. This can lead to unauthorized access to backend databases, internal APIs, and other sensitive resources that reside within the organization's trusted network boundaries. The vulnerability also enables attackers to use the compromised server as a pivot point for further attacks, potentially escalating privileges or moving laterally within the network infrastructure. Organizations with extensive XML-RPC.NET deployments face substantial risk of data breaches and unauthorized system access when this vulnerability remains unpatched.
The mitigation strategy for CVE-2022-47514 requires immediate deployment of the XML-RPC.NET version 2.5.0 or later, which includes proper XML parser configuration to disable external entity resolution. Organizations should also implement comprehensive input validation and sanitization for all XML-RPC requests, ensuring that external entity declarations are rejected or properly escaped. Network-level controls such as firewall rules and proxy configurations can provide additional defense-in-depth by restricting outbound network connections from vulnerable servers. Security teams should conduct thorough vulnerability assessments to identify all systems using affected versions of XML-RPC.NET and implement monitoring to detect potential exploitation attempts. The vulnerability aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and maps to ATT&CK technique T1190 (Exploit Public-Facing Application) and T1071.1004 (Application Layer Protocol: DNS) when used for reconnaissance activities.
This vulnerability demonstrates the critical importance of proper XML parsing security configurations in web applications and services. The flaw represents a classic example of how insufficient input validation at the parsing layer can create severe security implications, particularly when combined with authentication requirements that make exploitation more accessible. Organizations should implement regular security assessments of their XML processing components and maintain up-to-date libraries to prevent similar vulnerabilities from being exploited. The security community should also consider this vulnerability as part of broader XXE attack patterns and incorporate appropriate detection signatures into intrusion detection systems to identify potential exploitation attempts. Proper security awareness training for developers regarding XML parsing security best practices remains essential to prevent similar issues in custom implementations and third-party library usage.