Biblio

Historically, attackers have sought to manipulate programs through the corruption of return addresses, function pointers, and other control flow data. However, as protections like ASLR, stack canaries, and no-execute bits have made such attacks more difficult, data-oriented exploits have received increasing attention. Such exploits try to subvert a program by reading or writing non-control data, without introducing any foreign code or violating the program’s legitimate control flow graph. Recently, a data-oriented exploitation technique called memory cartography was introduced, in which an attacker navigates between allocated memory regions using a precompiled map to disclose sensitive program data. The efficacy of memory cartography is dependent on inter-region pointers being located at constant offsets within memory regions; thus, cartographic attacks are difficult to launch against memory regions like heaps and stacks that have nondeterministic layouts. In this paper, we lower the barrier to successful attacks against nondeterministic memory, demonstrating that pointers between regions of memory often possess unique “signatures” that allow attackers to identify them with high accuracy. These signatures are accurate even when the pointers reside in non-deterministic memory areas. In many real-world programs, this allows an attacker that is capable of reading bytes from a single heap to access all of process memory. Our findings underscore the importance of memory isolation via separate address spaces.

In this paper, we introduce DeadBolt, a new security framework for managing IoT network access. DeadBolt hides all of the devices in an IoT deployment behind an access point that implements deny-by-default policies for both incoming and outgoing traffic. The DeadBolt AP also forces high-end IoT devices to use remote attestation to gain network access; attestation allows the devices to prove that they run up-to-date, trusted software. For lightweight IoT devices which lack the ability to attest, the DeadBolt AP uses virtual drivers (essentially, security-focused virtual network functions) to protect lightweight device traffic. For example, a virtual driver might provide network intrusion detection, or encrypt device traffic that is natively cleartext. Using these techniques, and several others, DeadBolt can prevent realistic attacks while imposing only modest performance costs.

Virtualization enables datacenter operators to safely run computations that belong to untrusted tenants. An ideal virtual machine has three properties: a small memory footprint; strong isolation from other VMs and the host OS; and the ability to maintain in-memory state across client requests. Unfortunately, modern virtualization technologies cannot provide all three properties at once. In this paper, we explain why, and propose a new virtualization approach, called Alto, that virtualizes at the layer of a managed runtime interface. Through careful design of (1) the application-facing managed interface and (2) the internal runtime architecture, Alto provides VMs that are small, secure, and stateful. Conveniently, Alto also simplifies VM operations like suspension, migration, and resumption. We provide several details about the proposed design, and discuss the remaining challenges that must be solved to fully realize the Alto vision.

In theory, remote attestation is a powerful primitive for building distributed systems atop untrusting peers. Unfortunately, the canonical attestation framework defined by the Trusted Computing Group is insufficient to express rich contextual relationships between client-side software components. Thus, attestors and verifiers must rely on ad-hoc mechanisms to handle real-world attestation challenges like attestors that load executables in nondeterministic orders, or verifiers that require attestors to track dynamic information flows between attestor-side components. In this paper, we survey these practical attestation challenges. We then describe a new attestation framework, named Cobweb, which handles these challenges. The key insight is that real-world attestation is a graph problem. An attestation message is a graph in which each vertex is a software component, and has one or more labels, e.g., the hash value of the component, or the raw file data, or a signature over that data. Each edge in an attestation graph is a contextual relationship, like the passage of time, or a parent/child fork() relationship, or a sender/receiver IPC relationship. Cobweb's verifier-side policies are graph predicates which analyze contextual relationships. Experiments with real, complex software stacks demonstrate that Cobweb's abstractions are generic and can support a variety of real-world policies.