  Intel Software Guard Extensions (SGX) provides a trusted execution
environment (TEE) to run code and operate sensitive data. SGX provides runtime
hardware protection where both code and data are protected even if other code
components are malicious. However, recently many attacks targeting SGX have
been identified and introduced that can thwart the hardware defence provided by
SGX. In this paper we present a survey of all attacks specifically targeting
Intel SGX that are known to the authors, to date. We categorized the attacks
based on their implementation details into 7 different categories. We also look
into the available defence mechanisms against identified attacks and categorize
the available types of mitigations for each presented attack.
