Biblio

Control flow integrity (CFI) has received significant attention in the community to combat control hijacking attacks in the presence of memory corruption vulnerabilities. The challenges in creating a practical CFI has resulted in the development of a new type of CFI based on runtime type checking (RTC). RTC-based CFI has been implemented in a number of recent practical efforts such as GRSecurity Reuse Attack Protector (RAP) and LLVM-CFI. While there has been a number of previous efforts that studied the strengths and limitations of other types of CFI techniques, little has been done to evaluate the RTC-based CFI. In this work, we study the effectiveness of RTC from the security and practicality aspects. From the security perspective, we observe that type collisions are abundant in sufficiently large code bases but exploiting them to build a functional attack is not straightforward. Then we show how an attacker can successfully bypass RTC techniques using a variant of ROP attacks that respect type checking (called TROP) and also built two proof-of-concept exploits, one against Nginx web server and the other against Exim mail server. We also discuss practical challenges of implementing RTC. Our findings suggest that while RTC is more practical for applying CFI to large code bases, its policy is not strong enough when facing a motivated attacker.

Network protocols such as Ethernet and TCP/IP were not designed to ensure the security and privacy of users. To protect users' privacy, anonymity networks such as Tor have been proposed to hide both identities and communication contents for Internet traffic. However, such solutions cannot protect enterprise network traffic that does not transit the Internet. In this paper, we present the design, implementation, and evaluation of a moving target technique called Packet Header Randomization (PHEAR), a privacy-enhancing system for enterprise networks that leverages emerging Software-Defined Networking hardware and protocols to eliminate identifiers found at the MAC, Network, and higher layers of the network stack. PHEAR also encrypts all packet data beyond the Network layer. We evaluate the security of PHEAR against a variety of known and novel attacks and conduct whole-network experiments that show the prototype deployment provides sufficient performance for common applications such as web browsing and file sharing.