Two graduate students from UC San Diego’s computer science department—Erik Buchanan and Ryan Roemer—have just published work showing that the process of building bad programs from good code using “return-oriented programming” can be automated and that this vulnerability applies to RISC computer architectures and not just the x86 architecture (which includes the vast majority of personal computers).
This new automation and generalization work from graduate students and professors from UC San Diego’s Jacobs School of Engineering will be presented on October 28 at ACM’s Conference on Communications and Computer Security (CCS) 2008, one of the premier academic computer security conferences.
“Most computer security defenses are based on the notion that preventing the introduction of malicious code is sufficient to protect a computer. This assumption is at the core of trusted computing, anti-virus software, and various defenses like Intel and AMD’s no execute protections. There is a subtle fallacy in the logic, however: simply keeping out bad code is not sufficient to keep out bad computation,” said UC San Diego computer science professor Stefan Savage, an author on the CCS 2008 paper.
Return-oriented programming exploits start out like more familiar attacks on computers. The attacker takes advantage of a programming error in the target system to overwrite the runtime stack and divert program execution away from the path intended by the system’s designers. But instead of injecting outside code—the approach used in traditional malicious exploits—return-oriented programming enables attackers to create any kind of nasty computation or program by using just the existing code.
“You can create any kind of malicious program you can imagine—Turing complete functionality,” said Shacham.
For example, a user’s Web browser could be subverted to record passwords typed by the user or to send spam e-mail to all address book contacts, using only the code that makes up the browser itself.
“There is value in showing just how big of a potential problem return-oriented programming may turn out to be,” said computer science graduate student Erik Buchanan.
The term “return-oriented programming” describes the fact that the “good” instructions that can be strung together in order to build malicious programs need to end with a return command. The graduate students showed that the process of building these malicious programs from good code can be largely automated by grouping sets of instructions into “gadgets” and then abstracting much of the tedious work behind a programming language and compiler.
Imagine taking a 700 page book, picking and choosing words and phrases in no particular order and then assembling a 50 page story that has nothing to do with the original book. Return-oriented programming allows you to do something similar. Here the 700 page book is the code that makes up the system being attacked—for example, the standard C-language library libc—and the story is the malicious program the attacker wishes to have executed.
“We found that return-oriented programming poses a much more general vulnerability than people initially thought,” said computer science graduate student Ryan Roemer. He and Buchanan chose to study return-oriented programming for a class project after they heard Shacham outline a series of open questions in a guest lecture he gave in Savage’s computer security course last winter.
Living with Return-Oriented Programming
“The threat posed by return-oriented programming, across all architectures and systems, has negative implications for an entire class of security mechanisms: those that seek to prevent malicious computation by preventing the execution of malicious code,” the authors write in their CCS 2008 paper.
For instance, Intel and AMD have implemented security functionality into their chips (NX/XD) that prevents code from being executed from certain memory regions. Operating systems in turn use these features to prevent input data from being executed as code (e.g., Microsoft’s Data Execution Prevention feature introduced in Windows XP SP2). The new research from UC San Diego, however, highlights an entire class of exploits that would not be stopped by these security measures since no malicious code is actually executed. Instead, the stack is “hijacked” and forced to run good code in bad ways.
“We have demonstrated that return-oriented exploits are practical to write, as the complexity of gadget combination is abstracted behind a programming language and compiler. Finally, we argue that this approach provides a simple bypass for the vast majority of exploitation mitigations in use today,” the computer scientists write.
The authors outline a series of approaches to combat return-oriented programming. Eliminating vulnerabilities permitting control flow manipulation remains a high priority—as it has for 20 years. Other possibilities: hardware and software support for further constraining control flow and addressing the power of the return-oriented approach itself.
“Finally, if the approaches fail, we may be forced to abandon the convenient model that code is statically either good or bad, and instead focus on dynamically distinguishing whether a particular execution stream exhibits good or bad behavior,” the authors write.
"When Good Instructions Go Bad: Generalizing Return-Oriented Programming to RISC," by Erik Buchanan, Ryan Roemer, Hovav Shacham, and Stefan Savage, Department of Computer Science & Engineering University of California, San Diego's Jacobs School of Engineering.
This work was made possible by the National Science Foundation (NSF).
Daniel Kane | EurekAlert!
Brown researchers teach computers to see optical illusions
24.09.2018 | Brown University
One Step Ahead: Adaptive Radar Systems for Smart Driver Assistance
20.09.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR
The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.
This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.
Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...
Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.
"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...
A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.
Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...
Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.
An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...
21.09.2018 | Event News
03.09.2018 | Event News
27.08.2018 | Event News
24.09.2018 | Physics and Astronomy
24.09.2018 | Earth Sciences
24.09.2018 | Health and Medicine