CVE-2018-1000526 in openpsa
Summary
by MITRE
Openpsa contains a XML Injection vulnerability in RSS file upload feature that can result in Remote denial of service. This attack appear to be exploitable via Specially crafted XML file. This vulnerability appears to have been fixed in after commit 4974a26.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability identified as CVE-2018-1000526 resides within the Openpsa application's RSS file upload functionality, representing a significant XML injection flaw that could be leveraged for remote denial of service attacks. This vulnerability specifically affects the processing of XML data within the RSS feed upload mechanism, where insufficient input validation and sanitization allows malicious actors to inject crafted XML content that can disrupt normal application operations. The flaw manifests when the system attempts to parse and process specially crafted XML files that contain malicious payloads designed to exploit the XML processing libraries or parsers used by the application. The vulnerability's exploitation requires an attacker to upload a maliciously constructed XML file that can trigger unexpected behavior in the XML parser or cause resource exhaustion during parsing operations.
The technical nature of this vulnerability aligns with CWE-91 and CWE-92, which classify XML injection and XML external entity processing issues respectively. These weaknesses fall under the broader category of injection vulnerabilities that can lead to various security consequences including denial of service, information disclosure, and potentially more severe impacts depending on the application's architecture and the XML parser implementation. The vulnerability's classification as an XML injection issue indicates that the application fails to properly validate or sanitize XML input before processing, allowing attackers to inject malicious XML constructs that can cause the XML parser to behave unexpectedly. The specific impact of this vulnerability is a remote denial of service condition where the malicious XML content can cause the application to crash, consume excessive resources, or become unresponsive during the processing of the crafted XML file.
From an operational perspective, this vulnerability presents a substantial risk to Openpsa deployments since it allows remote attackers to potentially disrupt service availability without requiring authentication or privileged access. The attack vector through file upload means that an attacker could potentially exploit this vulnerability through various means including web application interfaces, automated upload mechanisms, or even through social engineering if users are tricked into uploading malicious files. The vulnerability's exploitation via specially crafted XML files suggests that the attack could be executed through automated tools or scripts that generate XML content designed to trigger specific parsing behaviors that lead to denial of service conditions. The fact that this vulnerability was reportedly fixed after commit 4974a26 indicates that the developers implemented proper input validation and sanitization measures to prevent malicious XML content from being processed, likely through the implementation of XML parser configurations that disable external entity resolution or through proper XML schema validation.
The mitigation strategies for this vulnerability should focus on implementing robust input validation and sanitization for all XML content processed by the application, particularly within file upload mechanisms. Organizations should ensure that XML parsers are configured to disable external entity resolution and other potentially dangerous XML features that could be exploited. The fix implemented after commit 4974a26 likely involved strengthening the XML processing pipeline to reject or properly sanitize any malformed or malicious XML content before it can cause disruption to the application's normal operations. Additionally, implementing proper access controls and upload restrictions, such as file type validation and size limits, can further reduce the attack surface for this type of vulnerability. Security monitoring and logging of file upload activities should also be enhanced to detect and respond to potential exploitation attempts, as this vulnerability could be part of broader attack patterns targeting web application file upload functionality. The remediation process should also include thorough testing of the XML processing components to ensure that the implemented fixes do not introduce new vulnerabilities while effectively addressing the original injection flaw.