CVE-2018-18013 in Xen Mobile
Summary
by MITRE
** DISPUTED *** Xen Mobile through 10.8.0 includes a service listening on port 5001 within its firewall that accepts unauthenticated input. If this service is supplied with raw serialised Java objects, it deserialises them back into Java objects in memory, giving rise to a remote code execution vulnerability. NOTE: the vendor disputes that this is a vulnerability, stating it is "already mitigated by the internal firewall that limits access to configuration services to localhost."
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2018-18013 affects Xen Mobile versions through 10.8.0 and represents a critical remote code execution risk stemming from improper input validation within the application's security architecture. This issue manifests through a service operating on port 5001 that accepts raw serialized Java objects without authentication, creating an attack surface that can be exploited by malicious actors to execute arbitrary code on affected systems. The flaw exists within the deserialization mechanism that processes incoming data without adequate sanitization, allowing attackers to craft malicious payloads that, when processed, can lead to complete system compromise. This vulnerability type aligns with CWE-502, which specifically addresses deserialization of untrusted data as a significant security weakness. The attack vector involves sending serialized Java objects to the exposed service, which then deserializes these objects in memory, potentially executing malicious code with the privileges of the running service.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within network environments. When exploited, attackers can gain unauthorized access to sensitive data, modify system configurations, install backdoors, or use the compromised system as a pivot point for attacking other networked devices. The vulnerability's severity is amplified by the fact that it operates without authentication requirements, making it particularly dangerous in environments where the service might be exposed to untrusted networks or where internal security boundaries are not properly enforced. The deserialization flaw creates a persistent threat that can be exploited repeatedly, as the underlying service continues to accept and process serialized objects without proper validation mechanisms.
Despite the vendor's claim that this issue is mitigated by internal firewall restrictions limiting access to localhost, this assertion raises significant concerns about the overall security posture of the affected systems. The vendor's position suggests that the vulnerability exists primarily in configurations where the service is exposed beyond its intended scope, but this defense-in-depth approach is insufficient for organizations with complex network architectures or those that may have misconfigured firewall rules. The vulnerability's classification as disputed by the vendor does not diminish its potential impact, as the security community recognizes that exposing deserialization services to network traffic, even with firewall restrictions, creates inherent risks that may be bypassed or circumvented. Organizations implementing security controls should consider this vulnerability as a potential threat regardless of the vendor's stance.
Mitigation strategies for CVE-2018-18013 should focus on both immediate defensive measures and long-term architectural improvements to prevent similar vulnerabilities from emerging. The most effective immediate solution involves restricting access to port 5001 through proper firewall configuration, ensuring that the service operates exclusively within the localhost boundary as the vendor claims is sufficient. Additionally, organizations should implement network segmentation to isolate critical services and apply principle of least privilege access controls to prevent unauthorized network access to internal services. The implementation of input validation and sanitization mechanisms should be enforced at all levels of the application stack, particularly for any service that processes external input. Organizations should also consider implementing intrusion detection systems to monitor for unusual patterns of network traffic targeting port 5001 and establish regular security assessments to identify potential exposure of internal services to untrusted networks. The vulnerability's nature also suggests that regular application updates and patch management processes should be prioritized, as the vendor's response indicates that such issues may be addressed through software updates that strengthen the service's security posture.
The technical exploitation of this vulnerability aligns with ATT&CK technique T1059.007, which covers the use of Java for remote code execution, demonstrating how deserialization flaws can be leveraged to achieve persistent access and control over target systems. The vulnerability also reflects broader security concerns related to insecure deserialization practices that have been documented in numerous security advisories and threat intelligence reports, emphasizing the importance of addressing these architectural weaknesses through comprehensive security design principles and regular vulnerability assessments.