CVE-2016-4931 in Junos Space
Summary
by MITRE
XML entity injection in Junos Space before 15.2R2 allows attackers to cause a denial of service.
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Analysis
by VulDB Data Team • 09/10/2020
The vulnerability CVE-2016-4931 represents a critical XML entity injection flaw discovered in Junos Space software versions prior to 15.2R2. This vulnerability resides within the XML processing mechanisms of the Junos Space platform, which serves as a network management solution for juniper networks devices. The flaw enables malicious actors to exploit the system's handling of XML entities through crafted input sequences that can trigger unexpected behavior within the application's XML parser.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of XML input data within the Junos Space management interface. When the system processes XML entities containing recursive or excessive references, it fails to properly limit the expansion of these entities, creating a condition where attacker-controlled input can cause the parser to consume excessive system resources or enter an infinite loop. This specific weakness maps to CWE-611, which categorizes improper restriction of XML external entity references as a fundamental security flaw that can lead to various attack vectors including denial of service, information disclosure, and potentially remote code execution depending on the application's architecture.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can severely disrupt network management operations and compromise the availability of critical infrastructure monitoring capabilities. Organizations relying on Junos Space for network device management face significant risk when operating vulnerable versions, as attackers can exploit this weakness to exhaust system resources, causing legitimate users to lose access to management functions. The attack surface is particularly concerning given that Junos Space serves as a central management platform for enterprise networks, making it an attractive target for adversaries seeking to disrupt business operations and network visibility.
Mitigation strategies for CVE-2016-4931 require immediate implementation of the vendor-provided security patches and updates to Junos Space versions 15.2R2 and later. Network administrators should also implement network segmentation and access controls to limit exposure of vulnerable systems to untrusted networks. The remediation process must include thorough testing of updated configurations to ensure that legitimate XML processing functionality remains intact while eliminating the vulnerability. Organizations should also consider implementing additional monitoring and logging mechanisms to detect potential exploitation attempts and establish incident response procedures specifically addressing XML injection attacks. This vulnerability demonstrates the importance of proper input validation and the principle of least privilege in network management systems, aligning with ATT&CK technique T1210 for exploitation of remote services and T1499 for denial of service attacks.