Intel SGX provided a mechanism to better isolate user-level software from attackers. However, attackers will still use various methods to attack SGX and user’s Enclaves. And user’s code inside Enclave may also have bugs, which can be leveraged by the attackers. We are from intel SGX SDK team, we have conducted security analysis and pen-test for SGX Enclave (based on SGX SDK) during the past 10+ years. We want to summarize some past exploits we encountered in our daily work and what's the mitigation, hope it can help the Enclave developers to write more secure Enclave code. Target topics category: TEE-specific attacks and defenses (vulnerabilities, exploits, defensive programming) Purpose: Explain the Security Properties of Intel® SGX Technology. Help Enclave Developers write more secure code within an enclave. Analyze a sampling of enclave defense-in-depth strategies and protections against known attacks. SGX Enclave Security and Challenge: Code running within the enclave must be written securely. Poorly written code may be subject to attack by various methods. Developers must also be aware of potential side-channel attacks on code.