The large-scale monitoring of computer users' software activities has become commonplace, e.g., for application telemetry, error reporting, or demographic profiling. This paper describes a principled systems architecture---Encode, Shuffle, Analyze (ESA)---for performing such monitoring with high utility while also protecting user privacy. The ESA design, and its Prochlo implementation, are informed by our practical experiences with an existing, large deployment of privacy-preserving software monitoring.

Control flow integrity (CFI) restricts jumps and branches within a program to prevent attackers from executing arbitrary code in vulnerable programs. However, traditional CFI still offers attackers too much freedom to chose between valid jump targets, as seen in recent attacks.

We show that it is possible to write remote stack buffer overflow exploits without possessing a copy of the target binary or source code, against services that restart after a crash. This makes it possible to hack proprietary closed-binary services, or open-source servers manually compiled and installed from source where the binary remains unknown to the attacker. Traditional techniques are usually paired against a particular binary and distribution where the hacker knows the location of useful gadgets for Return Oriented Programming (ROP). Our Blind ROP (BROP) attack instead remotely finds enough ROP gadgets to perform a write system call and transfers the vulnerable binary over the network, after which an exploit can be completed using known techniques. This is accomplished by leaking a single bit of information based on whether a process crashed or not when given a particular input string. BROP requires a stack vulnerability and a service that restarts after a crash. We implemented Braille, a fully automated exploit that yielded a shell in under 4,000 requests (20 minutes) against a contemporary nginx vulnerability, yaSSL + MySQL, and a toy proprietary server written by a colleague. The attack works against modern 64-bit Linux with address space layout randomization (ASLR), no-execute page protection (NX) and stack canaries.

Ori is a file system that manages user data in a modern setting where users have multiple devices and wish to access files everywhere, synchronize data, recover from disk failure, access old versions, and share data. The key to satisfying these needs is keeping and replicating file system history across devices, which is now practical as storage space has outpaced both wide-area network (WAN) bandwidth and the size of managed data. Replication provides access to files from multiple devices. History provides synchronization and offline access. Replication and history together subsume backup by providing snapshots and avoiding any single point of failure. In fact, Ori is fully peer-to-peer, offering opportunistic synchronization between user devices in close proximity and ensuring that the file system is usable so long as a single replica remains. Cross-file system data sharing with history is provided by a new mechanism called grafting. An evaluation shows that as a local file system, Ori has low overhead compared to a File system in User Space (FUSE) loopback driver; as a network file system, Ori over a WAN outperforms NFS over a LAN.

The 802.11 encryption standard Wired Equivalent Privacy (WEP) is still widely used today despite the numerous discussions on its insecurity. In this paper, we present a novel vulnerability which allows an attacker to send arbitrary data on a WEP network after having eavesdropped a single data packet. Furthermore, we present techniques for real-time decryption of data packets, which may be used under common circumstances. Vendor produced mitigation techniques which cause frequent WEP re-keying prevent traditional attacks, whereas our attack remains effective even in such scenarios. We implemented a fully automatic version of this attack which demonstrates its practicality and feasibility in real networks. As even rapidly re-keyed networks can be quickly compromised, we believe WEP must now be abandoned rather than patched yet again.