Trusted Execution Environments (TEEs) are gaining popularity as an effective means to provide confidentiality in the cloud. TEEs, such as Intel SGX, suffer from so-called rollback and cloning attacks (often referred to as forking attacks). Rollback attacks are enabled by the lack of freshness guarantees for sealed data; cloning attacks stem from the inability to determine if other instances of an enclave are running on the same platform. While rollback attacks have been extensively studied by the community, cloning attacks have been, unfortunately, less investigated. To address this gap, we extensively study and thoroughly analyze the susceptibility of 72 SGX-based proposals to cloning attacks. Our results show that roughly 20% of the analyzed proposals are insecure against cloning attacks-including those applications that rely on monotonic counters and are, therefore, secure against rollback attacks.

翻译：可信执行环境（TEE）作为一种在云环境中提供机密性的有效手段正日益普及。诸如Intel SGX之类的TEE存在所谓的回滚和克隆攻击（通常称为分叉攻击）。回滚攻击源于密封数据缺乏新鲜性保证；克隆攻击则源于无法确定同一平台上是否运行着其他飞地实例。尽管学术界已对回滚攻击进行了广泛研究，但遗憾的是，克隆攻击的研究相对不足。为填补这一空白，我们深入研究了72项基于SGX的方案对克隆攻击的脆弱性，并进行了全面分析。研究结果表明，约20%的被分析方案对克隆攻击存在安全隐患——这包括那些依赖单调计数器因而能抵御回滚攻击的应用。