CVE-2016-2945 in WebSphere Application Server
Summary
by MITRE
The API Discovery implementation in IBM WebSphere Application Server (WAS) 8.5.5.8 through 8.5.5.9 Liberty before Liberty Fix Pack 16.0.0.2 allows remote authenticated users to gain privileges via an external reference in a Swagger document.
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Analysis
by VulDB Data Team • 02/18/2019
The vulnerability identified as CVE-2016-2945 resides within the API Discovery feature of IBM WebSphere Application Server Liberty profile versions 8.5.5.8 through 8.5.5.9. This flaw represents a critical security weakness that enables remote authenticated attackers to escalate their privileges through manipulation of Swagger documentation references. The issue stems from insufficient validation of external references within API discovery mechanisms, creating a pathway for unauthorized privilege escalation. The vulnerability operates by allowing attackers to craft malicious Swagger documents containing external references that can be processed by the server's API discovery service, potentially leading to unauthorized access to system resources and elevated privileges. This type of vulnerability falls under the category of insecure deserialization and improper access control as classified by CWE-20 and CWE-285 respectively. The impact extends beyond simple privilege escalation to potentially enable attackers to access sensitive system information, modify critical configurations, or gain unauthorized access to protected resources within the application server environment.
The technical exploitation of this vulnerability occurs through the manipulation of Swagger documentation files that are processed by the API Discovery service. When the Liberty profile processes these documents, it fails to properly validate external references, allowing attackers to include malicious references that point to external resources or internal system endpoints. The flaw specifically affects the way the server handles external references in Swagger documents, where it does not adequately sanitize or restrict access to these references. Attackers can leverage this by creating Swagger documents with external references pointing to internal resources or by exploiting the server's ability to resolve these references in ways that bypass normal access controls. This vulnerability directly relates to the ATT&CK technique T1078.004 which covers valid accounts and T1566 which involves malicious file execution through API manipulation. The implementation flaw exists in the API Discovery component of the Liberty profile, which processes API documentation without proper validation of external resource references, creating an attack surface that allows for privilege escalation through controlled manipulation of these references.
The operational impact of CVE-2016-2945 extends significantly beyond the immediate privilege escalation capabilities, as it can enable attackers to compromise entire application server environments. Organizations running affected versions of IBM WebSphere Liberty profile are at risk of unauthorized access to sensitive data, system configuration information, and potentially complete server compromise. The vulnerability affects the core security posture of applications deployed on these servers, as it allows attackers to bypass normal authentication and authorization mechanisms that should protect privileged system resources. This weakness particularly impacts organizations that rely heavily on API discovery features for application development and deployment, as it creates a persistent threat vector that can be exploited by attackers who have gained initial access through other means. The vulnerability also creates opportunities for attackers to escalate their access to higher privilege levels, potentially enabling them to modify application configurations, access restricted databases, or perform administrative functions on the server. From a compliance perspective, this vulnerability can result in violations of security standards such as those outlined in NIST SP 800-53 and ISO 27001, particularly in areas related to access control and privilege management.
Mitigation strategies for CVE-2016-2945 primarily focus on applying the official IBM Liberty Fix Pack 16.0.0.2 which addresses the specific validation issues in the API Discovery implementation. Organizations should also implement network segmentation to limit access to the API Discovery service, restrict external references in Swagger documents, and implement monitoring for unusual API discovery activity. Additional protective measures include disabling API Discovery features when not required, implementing strict access controls for Swagger document uploads, and conducting regular security assessments of API endpoints. Security teams should also consider implementing web application firewalls to filter malicious Swagger documents and establish proper logging and monitoring of API discovery activities. The vulnerability demonstrates the importance of proper input validation and external reference handling in security-critical components, aligning with security best practices outlined in OWASP Top 10 and NIST Cybersecurity Framework. Organizations should also implement regular patch management processes to ensure timely deployment of security fixes and maintain updated threat intelligence to identify similar vulnerabilities in other components of their application stack.