Biblio

Despite decades of research on software diversification, only address space layout randomization has seen widespread adoption. Code randomization, an effective defense against return-oriented programming exploits, has remained an academic exercise mainly due to i) the lack of a transparent and streamlined deployment model that does not disrupt existing software distribution norms, and ii) the inherent incompatibility of program variants with error reporting, whitelisting, patching, and other operations that rely on code uniformity. In this work we present compiler-assisted code randomization (CCR), a hybrid approach that relies on compiler-rewriter cooperation to enable fast and robust fine-grained code randomization on end-user systems, while maintaining compatibility with existing software distribution models. The main concept behind CCR is to augment binaries with a minimal set of transformation-assisting metadata, which i) facilitate rapid fine-grained code transformation at installation or load time, and ii) form the basis for reversing any applied code transformation when needed, to maintain compatibility with existing mechanisms that rely on referencing the original code. We have implemented a prototype of this approach by extending the LLVM compiler toolchain, and developing a simple binary rewriter that leverages the embedded metadata to generate randomized variants using basic block reordering. The results of our experimental evaluation demonstrate the feasibility and practicality of CCR, as on average it incurs a modest file size increase of 11.46% and a negligible runtime overhead of 0.28%, while it is compatible with link-time optimization and control flow integrity.

Control-hijacking attacks include code injection attacks and code reuse attacks. In recent years, with the emergence of the defense mechanism data-execution prevention(DEP), code reuse attacks have become mainstream, such as return-oriented programming(ROP), Jump-Oriented Programming(JOP), and Counterfeit Object-oriented Programming(COOP). And a series of defensive measures have been proposed, such as DEP, address space layout randomization (ASLR), coarse-grained Control-Flow Integrity(CFI) and fine-grained CFI. In this paper, we propose a new attack called function-oriented programming(FOP) to construct malicious program behavior. FOP takes advantage of the existing function of the C program to induce attack. We propose concrete algorithms for FOP gadgets and build a tool to identify FOP gadgets. FOP can successfully bypass coarse-grained CFI, and FOP also can bypass some existing fine-grained CFI technologies, such as shadow stack technology. We show a real-world attack for proftpd1.3.0 server in the Linux x64 environment. We believe that the FOP attack will encourage people to come up with more effective defense measures.

Many modern defenses rely on address space layout randomization (ASLR) to efficiently hide security-sensitive metadata in the address space. Absent implementation flaws, an attacker can only bypass such defenses by repeatedly probing the address space for mapped (security-sensitive) regions, incurring a noisy application crash on any wrong guess. Recent work shows that modern applications contain idioms that allow the construction of crash-resistant code primitives, allowing an attacker to efficiently probe the address space without causing any visible crash. In this paper, we classify different crash-resistant primitives and show that this problem is much more prominent than previously assumed. More specifically, we show that rather than relying on labor-intensive source code inspection to find a few "hidden" application-specific primitives, an attacker can find such primitives semi-automatically, on many classes of real-world programs, at the binary level. To support our claims, we develop methods to locate such primitives in real-world binaries. We successfully identified 29 new potential primitives and constructed proof-of-concept exploits for four of them.