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Han, Wonkyu, Hu, Hongxin, Zhao, Ziming, Doupé, Adam, Ahn, Gail-Joon, Wang, Kuang-Ching, Deng, Juan.  2016.  State-aware Network Access Management for Software-Defined Networks. Proceedings of the 21st ACM on Symposium on Access Control Models and Technologies. :1–11.

OpenFlow, as the prevailing technique for Software-Defined Networks (SDNs), introduces significant programmability, granularity, and flexibility for many network applications to effectively manage and process network flows. However, because OpenFlow attempts to keep the SDN data plane simple and efficient, it focuses solely on L2/L3 network transport and consequently lacks the fundamental ability of stateful forwarding for the data plane. Also, OpenFlow provides a very limited access to connection-level information in the SDN controller. In particular, for any network access management applications on SDNs that require comprehensive network state information, these inherent limitations of OpenFlow pose significant challenges in supporting network services. To address these challenges, we propose an innovative connection tracking framework called STATEMON that introduces a global state-awareness to provide better access control in SDNs. STATEMON is based on a lightweight extension of OpenFlow for programming the stateful SDN data plane, while keeping the underlying network devices as simple as possible. To demonstrate the practicality and feasibility of STATEMON, we implement and evaluate a stateful network firewall and port knocking applications for SDNs, using the APIs provided by STATEMON. Our evaluations show that STATEMON introduces minimal message exchanges for monitoring active connections in SDNs with manageable overhead (3.27% throughput degradation).

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Rubio-Medrano, Carlos E., Zhao, Ziming, Ahn, Gail-Joon.  2018.  RiskPol : A Risk Assessment Framework for Preventing Attribute-Forgery Attacks to ABAC Policies. Proceedings of the Third ACM Workshop on Attribute-Based Access Control. :54–60.

Recently, attribute-based access control (ABAC) has emerged as a convenient paradigm for specifying, enforcing and maintaining rich and flexible authorization policies, leveraging attributes originated from multiple sources, e.g., operative systems, software modules, remote services, etc. However, attackers may try to bypass ABAC policies by compromising such sources to forge the attributes they provide, e.g., by deliberately manipulating the data contained within those attributes at will, in an effort to gain unintended access to sensitive resources as a result. In such a context, performing a proper risk assessment of ABAC policies, taking into account their enlisted attributes as well as their corresponding sources, becomes highly convenient to overcome zero-day security incidents or vulnerabilities, before they can be later exploited by attackers. With this in mind, we introduce RiskPol, an automated risk assessment framework for ABAC policies based on dynamically combining previously-assigned trust scores for each attribute source, such that overall scores at the policy level can be later obtained and used as a reference for performing a risk assessment on each policy. In this paper, we detail the general intuition behind our approach, its current status, as well as our plans for future work.

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Rubio-Medrano, Carlos E., Lamp, Josephine, Doupé, Adam, Zhao, Ziming, Ahn, Gail-Joon.  2017.  Mutated Policies: Towards Proactive Attribute-based Defenses for Access Control. Proceedings of the 2017 Workshop on Moving Target Defense. :39–49.
Recently, both academia and industry have recognized the need for leveraging real-time information for the purposes of specifying, enforcing and maintaining rich and flexible authorization policies. In such a context, security-related properties, a.k.a., attributes, have been recognized as a convenient abstraction for providing a well-defined representation of such information, allowing for them to be created and exchanged by different independently-run organizational domains for authorization purposes. However, attackers may attempt to compromise the way attributes are generated and communicated by recurring to hacking techniques, e.g., forgery, in an effort to bypass authorization policies and their corresponding enforcement mechanisms and gain unintended access to sensitive resources as a result. In this paper, we propose a novel technique that allows for enterprises to pro-actively collect attributes from the different entities involved in the access request process, e.g., users, subjects, protected resources, and running environments. After the collection, we aim to carefully select the attributes that uniquely identify the aforementioned entities, and randomly mutate the original access policies over time by adding additional policy rules constructed from the newly-identified attributes. This way, even when attackers are able to compromise the original attributes, our mutated policies may offer an additional layer of protection to deter ongoing and future attacks. We present the rationale and experimental results supporting our proposal, which provide evidence of its suitability for being deployed in practice.
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Han, Wonkyu, Zhao, Ziming, Doupé, Adam, Ahn, Gail-Joon.  2016.  HoneyMix: Toward SDN-based Intelligent Honeynet. Proceedings of the 2016 ACM International Workshop on Security in Software Defined Networks & Network Function Virtualization. :1–6.

Honeynet is a collection of honeypots that are set up to attract as many attackers as possible to learn about their patterns, tactics, and behaviors. However, existing honeypots suffer from a variety of fingerprinting techniques, and the current honeynet architecture does not fully utilize features of residing honeypots due to its coarse-grained data control mechanisms. To address these challenges, we propose an SDN-based intelligent honeynet called HoneyMix. HoneyMix leverages the rich programmability of SDN to circumvent attackers' detection mechanisms and enables fine-grained data control for honeynet. To do this, HoneyMix simultaneously establishes multiple connections with a set of honeypots and selects the most desirable connection to inspire attackers to remain connected. In this paper, we present the HoneyMix architecture and a description of its core components.

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Dixit, Vaibhav Hemant, Kyung, Sukwha, Zhao, Ziming, Doupé, Adam, Shoshitaishvili, Yan, Ahn, Gail-Joon.  2018.  Challenges and Preparedness of SDN-based Firewalls. Proceedings of the 2018 ACM International Workshop on Security in Software Defined Networks & Network Function Virtualization. :33–38.

Software-Defined Network (SDN) is a novel architecture created to address the issues of traditional and vertically integrated networks. To increase cost-effectiveness and enable logical control, SDN provides high programmability and centralized view of the network through separation of network traffic delivery (the "data plane") from network configuration (the "control plane"). SDN controllers and related protocols are rapidly evolving to address the demands for scaling in complex enterprise networks. Because of the evolution of modern SDN technologies, production networks employing SDN are prone to several security vulnerabilities. The rate at which SDN frameworks are evolving continues to overtake attempts to address their security issues. According to our study, existing defense mechanisms, particularly SDN-based firewalls, face new and SDN-specific challenges in successfully enforcing security policies in the underlying network. In this paper, we identify problems associated with SDN-based firewalls, such as ambiguous flow path calculations and poor scalability in large networks. We survey existing SDN-based firewall designs and their shortcomings in protecting a dynamically scaling network like a data center. We extend our study by evaluating one such SDN-specific security solution called FlowGuard, and identifying new attack vectors and vulnerabilities. We also present corresponding threat detection techniques and respective mitigation strategies.

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Dixit, Vaibhav Hemant, Doupé, Adam, Shoshitaishvili, Yan, Zhao, Ziming, Ahn, Gail-Joon.  2018.  AIM-SDN: Attacking Information Mismanagement in SDN-Datastores. Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security. :664-676.

Network Management is a critical process for an enterprise to configure and monitor the network devices using cost effective methods. It is imperative for it to be robust and free from adversarial or accidental security flaws. With the advent of cloud computing and increasing demands for centralized network control, conventional management protocols like SNMP appear inadequate and newer techniques like NMDA and NETCONF have been invented. However, unlike SNMP which underwent improvements concentrating on security, the new data management and storage techniques have not been scrutinized for the inherent security flaws. In this paper, we identify several vulnerabilities in the widely used critical infrastructures which leverage the Network Management Datastore Architecture design (NMDA). Software Defined Networking (SDN), a proponent of NMDA, heavily relies on its datastores to program and manage the network. We base our research on the security challenges put forth by the existing datastore's design as implemented by the SDN controllers. The vulnerabilities identified in this work have a direct impact on the controllers like OpenDayLight, Open Network Operating System and their proprietary implementations (by CISCO, Ericsson, RedHat, Brocade, Juniper, etc). Using our threat detection methodology, we demonstrate how the NMDA-based implementations are vulnerable to attacks which compromise availability, integrity, and confidentiality of the network. We finally propose defense measures to address the security threats in the existing design and discuss the challenges faced while employing these countermeasures.