Phishing attacks continue to pose a major threat for computer system defenders, often forming the first step in a multi-stage attack. There have been great strides made in phishing detection; however, some phishing emails appear to pass through filters by making simple structural and semantic changes to the messages. We tackle this problem through the use of a machine learning classifier operating on a large corpus of phishing and legitimate emails. We design SAFe-PC (Semi-Automated Feature generation for Phish Classification), a system to extract features, elevating some to higher level features, that are meant to defeat common phishing email detection strategies. To evaluate SAFe-PC , we collect a large corpus of phishing emails from the central IT organization at a tier-1 university. The execution of SAFe-PC on the dataset exposes hitherto unknown insights on phishing campaigns directed at university users. SAFe-PC detects more than 70 percent of the emails that had eluded our production deployment of Sophos, a state-of-the-art email filtering tool. It also outperforms SpamAssassin, a commonly used email filtering tool. We also developed an online version of SAFe-PC, that can be incrementally retrained with new samples. Its detection performance improves with time as new samples are collected, while the time to retrain the classifier stays constant.
The paradigm that deceptive data, tools and behavior are difficult to distinguish from their legitimate counterparts is intuitively understood, but a formal representation of why deception works and its impact on the security provided by patches is lacking. As an emerging research area, it is important to develop this strong foundation from which to reason about the security impact of proposed techniques.Thus, we present a number of deceptive models that represent a variety of deceptive patches to move toward a formal model of deception. These models identify theoretically secure techniques as well as those that fall short of theoretical security. For techniques that fall short, additional analysis shows they could still be effective in practice.In this research, we first introduce formal game-based security definitions that capture the technique's claimed security impact and present a general game-based model using these definitions. We then apply this general model to faux, obfuscated, and active response patches to formally analyze their security impact. Finally, we discuss whether these ideal properties of deceptive systems can be achieved in reality.
Offensive and defensive players in the cyber security sphere constantly react to either party’s actions. This reactive approach works well for attackers but can be devastating for defenders. This approach also models the software security patching lifecycle. Patches fix security flaws, but when deployed, can be used to develop malicious exploits. To make exploit generation using patches more resource intensive, we propose inserting deception into software security patches. These ghost patches mislead attackers with deception and fix legitimate flaws in code. An adversary using ghost patches to develop exploits will be forced to use additional resources. We implement a proof of concept for ghost patches and evaluate their impact on program analysis and runtime. We find that these patches have a statistically significant impact on dynamic analysis runtime, increasing time to analyze by a factor of up to 14x, but do not have a statistically significant impact on program runtime.
While cyber attacks continue to evolve, deception remains a key feature during exploit generation. Because humans are the weakest link in the cyber security chain, using deception in exploits to mislead end users offers attackers a more probable path to system compromise. In this work, we present a novel analysis of deceptive component(s) in commonly observed offensive attacks. Specifically, we examine four attacks, including phishing and scamming, watering hole, clickbait and repackaging attacks. We present a model of the components of each of these attacks in which we highlight how deception is successfully used. We also identify recipient biases these deceptive components rely on to be successful and provide a basis for these biases using a corpus of phishing emails. Additionally, we suggest the prior success of exploits that employ deception translates to its' ability to improve computer defenses. We discuss frameworks that apply deceptive techniques to systems that defend against the four exploits we analyze as well as other offensive attacks and provide advantages and disadvantages for these approaches. We also discuss how these frameworks could be applied to cyber defense to enhance system security and expose information about attackers. We compare deceptive cyber defenses to more traditional defensive systems. We identify some recent work in deceptive defenses, our contributions in this work and directions for future research.
In this work, we present a simple, yet effective and practical scheme to improve the security of stored password hashes, increasing the difficulty to crack passwords and exposing cracking attempts. We utilize a hardware-dependent function (HDF), such as a physically unclonable function (PUF) or a hardware security module (HSM), at the authentication server to inhibit offline password discovery. Additionally, a deception mechanism is incorporated to alert administrators of cracking attempts. Using an HDF to generate password hashes hinders attackers from recovering the true passwords without constant access to the HDF. Our scheme can integrate with legacy systems without needing additional servers, changing the structure of the hashed password file, nor modifying client machines. When using our scheme, the structure of the hashed passwords file, e.g., etc/shadow or etc/master.passwd , will appear no different than traditional hashed password files. 1 However, when attackers exfiltrate the hashed password file and attempt to crack it, the passwords they will receive are ErsatzPasswords—“fake passwords.” The ErsatzPasswords scheme is flexible by design, enabling it to be integrated into existing authentication systems without changes to user experience. The proposed scheme is integrated into the pam_unix module as well as two client/server authentication schemes: Lightweight Directory Access Protocol (LDAP) authentication and the Pythia pseudorandom function (PRF) Service [Everspaugh et al. 2015]. The core library to support ErsatzPasswords written in C and Python consists of 255 and 103 lines of code, respectively. The integration of ErsatzPasswords into each explored authentication system required less than 100 lines of additional code. Experimental evaluation of ErsatzPasswords shows an increase in authentication latency on the order of 100ms, which maybe acceptable for real world systems. We also describe a framework for implementing ErsatzPasswords using a Trusted Platform Module (TPM).
Existing processes and methods for incident handling are geared towards infrastructures and operational models that will be increasingly outdated by cloud computing. Research has shown that to adapt incident handling to cloud computing environments, cloud customers must establish clarity about their requirements on Cloud Service Providers (CSPs) for successful handling of incidents and contract CSPs accordingly. Secondly, CSPs must strive to support these requirements and mirror them in their Service Level Agreements. Intrusion Detection Systems (IDS) have been used widely to detect malicious behaviors in network communication and hosts. Facing new application scenarios in Cloud Computing, the IDS approaches yield several problems since the operator of the IDS should be the user, not the administrator of the Cloud infrastructure. Cloud providers need to enable possibilities to deploy and configure IDS for the user - which poses its own challenges. Current research and commercial solutions primarily focus on protecting against Denial of Service attacks and attacks against the Cloud’s virtual infrastructure. To counter these challenges, we propose a capability that aims to both detect and prevent the potential of data exfiltration by using a novel deception-based methodology. We also introduce a method of increasing the data protection level based on various threat conditions.
Hypergames are a branch of game theory to model and analyze game theoretic conflicts between multiple players who may have misconceptions of other player's actions, preferences, and/or knowledge. They have been used to model military conflicts such as the Allied invasion of Normandy in 1945, the fall of France in WWII, the Cuban missile crisis, and etc. Unlike traditional game theory models, hypergames give us the ability to model misperception that results from the use of deception, mimicry, and misinformation. There is little work that analyzes the use of deception as a strategic defensive mechanism in computing systems. This poster will present a hypergame model to analyze computer security conflicts. We discuss how can hypergames be used to model the interaction between adversaries and system defender. We discuss a specific example where we modele the interaction between adversaries, who wish to steal some confidential data from an enterprise, and security administrators, who protect the system. We show the advantages of incorporating deception as a defenses mechanism as part of the hypergame model.
Deception is defined as "presenting an altered view of reality" and has been used by mankind for thousands of years to influence other's behavior and decision making. More recently, deception has also been applied to computing in a variety of areas, such as human computer interaction and digital communities. This work surveys different areas of computing to determine where and how they use deception. One area we study in particular is how deception is applied to security practices. This work also shows that while security is a growing field, deceptive practices have not been as readily adopted to improve defense.
Phishing attacks continue to pose a major headache for defenders of computing systems, often forming the first step in a multi-stage attacks. There have been great strides made in phishing detection and email servers have gotten good at flagging potentially phishing messages. However, some insidious kinds of phishing messages appear to pass through filters by making seemingly simple structural and semantic changes to the messages. We tackle this problem in this paper, through the use of machine learning algorithms operating on a large corpus of phishing messages and legitimate messages. By understanding common phishing features, we design a system to extract features and extrapolate out values of such features. The algorithms are specialized for phishing detection, such as, the use of synonyms or change in sentence structure. The insights and algorithms are instantiated in a system called SNIPE (Signature geNeratIon for Phishing Emails). To evaluate SNIPE, we collect the largest known corpus of phishing messages (used in any publicly known study) from the central IT organization at a tier-1 research university. We run SNIPE on the dataset and it exposes some hitherto unknown insights about phishing campaigns directed at university users. SNIPE is able to detect 100% of phishing messages that had eluded our production deployment of Sophos, a state-of-the-art email filtering tool today.