Self-Healing Multitier Architectures Using Cascading Rescue Points

Software bugs and vulnerabilities cause serious problems to both home users and the Internet infrastructure, limiting the availability of Internet services, causing loss of data, and reducing system integrity. Software self-healing using rescue points (RPs) is a known mechanism for recovering from unforeseen errors. However, applying it on multitier architectures can be problematic because certain actions, like transmitting data over the network, cannot be undone. We propose cascading rescue points (CRPs) to address the state inconsistency issues that can arise when using traditional RPs to recover from errors in interconnected applications. With CRPs, when an application executing within a RP transmits data, the remote peer is notified to also perform a checkpoint, so the communicating entities checkpoint in a coordinated, but loosely coupled way. Notifications are also sent when RPs successfully complete execution, and when recovery is initiated, so that the appropriate action is performed by remote parties. We developed a tool that implements CRPs by dynamically instrumenting binaries and transparently injecting notifications in the already established TCP channels between applications. We tested our tool with various applications, including the MySQL and Apache servers, and show that it allows them to successfully recover from errors, while incurring moderate overhead between 4.54% and 71.56%

iLeak: A Lightweight System for Detecting Inadvertent Information Leaks

Data loss incidents, where data of sensitive nature are exposed to the public, have become too frequent and have caused damages of millions of dollars to companies and other organizations. Repeatedly, information leaks occur over the Internet, and half of the time they are accidental, caused by user negligence, misconfiguration of software, or inadequate understanding of an application's functionality. This paper presents iLeak, a lightweight, modular system for detecting inadvertent information leaks. Unlike previous solutions, iLeak builds on components already present in modern computers. In particular, we employ system tracing facilities and data indexing services, and combine them in a novel way to detect data leaks. Our design consists of three components: uaudits are responsible for capturing the information that exits the system, while Inspectors use the indexing service to identify if the transmitted data belong to files that contain potentially sensitive information. The Trail Gateway handles the communication and synchronization of uaudits and Inspectors. We implemented iLeak on Mac OS X using DTrace and the Spotlight indexing service. Finally, we show that iLeak is indeed lightweight, since it only incurs 4% overhead on protected applications

Detecting Traffic Snooping in Anonymity Networks Using Decoys

Anonymous communication networks like Tor partially protect the confidentiality of their users' traffic by encrypting all intra-overlay communication. However, when the relayed traffic reaches the boundaries of the overlay network towards its actual destination, the original user traffic is inevitably exposed. At this point, unless end-to-end encryption is used, sensitive user data can be snooped by a malicious or compromised exit node, or by any other rogue network entity on the path towards the actual destination. We explore the use of decoy traffic for the detection of traffic interception on anonymous proxying systems. Our approach is based on the injection of traffic that exposes bait credentials for decoy services that require user authentication. Our aim is to entice prospective eavesdroppers to access decoy accounts on servers under our control using the intercepted credentials. We have deployed our prototype implementation in the Tor network using decoy IMAP and SMTP servers. During the course of six months, our system detected eight cases of traffic interception that involved eight different Tor exit nodes. We provide a detailed analysis of the detected incidents, discuss potential improvements to our system, and outline how our approach can be extended for the detection of HTTP session hijacking attacks

Exploiting Split Browsers for Efficiently Protecting User Data

Offloading complex tasks to a resource-abundant environment like the cloud, can extend the capabilities of resource constrained mobile devices, extend battery life, and improve user experience. Split browsing is a new paradigm that adopts this strategy to improve web browsing on devices like smartphones and tablets. Split browsers offload computation to the cloud by design; they are composed by two parts, one running on the thin client and one in the cloud. Rendering takes place primarily in the latter, while a bitmap or a simplified web page is communicated to the client. Despite its difference with traditional web browsing, split browsing still suffers from the same types of threats, such as cross-site scripting. In this paper, we propose exploiting the design of split browsers to also utilize cloud resources for protecting against various threats efficiently. We begin by systematically studying split browsing architectures, and then proceed to propose two solutions, in parallel and inline cloning, that exploit the inherent features of this new browsing paradigm to accurately and efficiently protect user data against common web exploits. Our preliminary results suggest that our framework can be efficiently applied to Amazon’s Silk, the most widely deployed at the time of writing, split browser

Taint-Exchange: A Generic System for Cross-Process and Cross-Host Taint Tracking

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Taint-Exchange: A Generic System for Cross-Process and Cross-Host Taint Tracking

Dynamic taint analysis (DTA) has been heavily used by security researchers for various tasks, including detecting unknown exploits, analyzing malware, preventing information leaks, and many more. Recently, it has been also utilized to track data across processes and hosts to shed light on the interaction of distributed components, but also for security purposes. This paper presents Taint-Exchange, a generic cross-process and cross-host taint tracking framework. Our goal is to provide researchers with a valuable tool for rapidly developing prototypes that utilize cross-host taint tracking. Taint-Exchange builds on the libdft open source data flow tracking framework for processes, so unlike previous work it does not require extensive maintenance and setup. It intercepts I/O related system calls to transparently multiplex fine-grained taint information into existing communication channels, like sockets and pipes. We evaluate Taint-Exchange using the popular lmbench suite, and show that it incurs only moderate overhead

Position-Independent Code Reuse:On the Effectiveness of ASLR in the Absence of Information Disclosure

Address-space layout randomization is a wellestablished defense against code-reuse attacks. However, it can be completely bypassed by just-in-time code-reuse attacks that rely on information disclosure of code addresses via memory or side-channel exposure. To address this fundamental weakness, much recent research has focused on detecting and mitigating information disclosure. The assumption being that if we perfect such techniques, we will not only maintain layout secrecy but also stop code reuse. In this paper, we demonstrate that an advanced attacker can mount practical code-reuse attacks even in the complete absence of information disclosure. To this end, we present Position-Independent Code-Reuse Attacks, a new class of codereuse attacks relying on the relative rather than absolute location of code gadgets in memory. By means of memory massaging, the attacker first makes the victim program generate a rudimentary ROP payload (for instance, containing code pointers that target instructions 'close' to relevant gadgets). Afterwards, the addresses in this payload are patched with small offsets via relative memory writes. To establish the practicality of such attacks, we present multiple Position-Independent ROP exploits against real-world software. After showing that we can bypass ASLR in current systems without requiring information disclosures, we evaluate the impact of our technique on other defenses, such as fine-grained ASLR, multi-variant execution, execute-only memory and re-randomization. We conclude by discussing potential mitigations