CVE-2018-3626 in SGX SDK
Summary
by MITRE
Edger8r tool in the Intel SGX SDK before version 2.1.2 (Linux) and 1.9.6 (Windows) may generate code that is susceptible to a side channel potentially allowing a local user to access unauthorized information.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability identified as CVE-2018-3626 affects the Edger8r tool within Intel Software Guard Extensions SDK across both Linux and Windows platforms. This tool serves as a critical component in the SGX development ecosystem, responsible for generating C/C++ wrapper code that facilitates communication between untrusted user space applications and trusted SGX enclaves. The flaw exists in versions prior to 2.1.2 for Linux and 1.9.6 for Windows, representing a significant security weakness in Intel's secure computing framework. The vulnerability stems from improper handling of memory operations during code generation, creating potential side channel attack vectors that could compromise the confidentiality guarantees provided by SGX enclaves.
The technical implementation of this vulnerability involves the Edger8r tool's generation of code that may contain memory access patterns susceptible to timing attacks and cache-based side channel exploits. When the tool processes enclave interface definitions, it creates wrapper functions that handle data marshaling between the enclave and user space. The flaw manifests in how these generated functions manage memory allocation and access patterns, potentially leaking information through observable timing differences or cache state changes. This represents a variant of side channel vulnerability categorized under CWE-310, specifically dealing with cryptographic side channels and information leakage through implementation flaws.
The operational impact of this vulnerability is substantial for developers and system administrators working with Intel SGX applications. A local attacker with access to the development environment could potentially exploit this weakness to extract sensitive information from the generated code or even from the enclave itself. The attack surface extends beyond simple code generation to include the possibility of information leakage during the compilation process, where the attacker might observe memory access patterns or timing variations that reveal secrets. This vulnerability undermines the fundamental security model of SGX by potentially allowing unauthorized information access through the development toolchain rather than the enclave execution environment itself.
Mitigation strategies for CVE-2018-3626 primarily involve updating to the patched versions of Intel SGX SDK, specifically version 2.1.2 for Linux and 1.9.6 for Windows. Organizations should implement comprehensive patch management procedures to ensure all development environments are updated promptly. Additionally, developers should consider implementing defensive programming practices in their enclave code, such as constant-time operations and memory access pattern randomization. The vulnerability aligns with ATT&CK technique T1059.001 for the development environment compromise and T1059.007 for potential information leakage through side channels. System administrators should also monitor for any unusual memory access patterns or timing variations in development environments that could indicate exploitation attempts. The fix addresses the root cause by modifying the Edger8r tool's code generation logic to eliminate predictable memory access patterns that could be exploited through side channel analysis.