CVE-2018-3689 in Software Guard Extensions Platform Software Component
Summary
by MITRE
AESM daemon in Intel Software Guard Extensions Platform Software Component for Linux before 2.1.102 can effectively be disabled by a local attacker creating a denial of services like remote attestation provided by the AESM.
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Analysis
by VulDB Data Team • 01/21/2020
The vulnerability identified as CVE-2018-3689 affects the AESM daemon within Intel Software Guard Extensions Platform Software Component for Linux systems. This daemon plays a critical role in facilitating remote attestation processes that are fundamental to the security architecture of Intel SGX applications. The issue stems from a design flaw that allows local attackers to effectively disable the AESM service through simple file system manipulations, thereby compromising the integrity of the entire attestation infrastructure.
The technical flaw manifests in the daemon's insufficient validation mechanisms when handling certain file system operations. Specifically, the AESM daemon does not properly validate the state of critical files or directories that control its operational status. A local attacker can exploit this weakness by creating or modifying specific files within the daemon's operational directory structure, which causes the daemon to enter a disabled state. This behavior violates the principle of least privilege and demonstrates a lack of proper access control validation within the system's security framework.
The operational impact of this vulnerability extends far beyond simple service disruption, as it fundamentally undermines the security model that Intel SGX applications depend upon for remote attestation. When the AESM daemon is disabled, legitimate remote attestation requests cannot be processed, leaving applications vulnerable to man-in-the-middle attacks and other security breaches that rely on verified enclave identities. This vulnerability directly impacts the confidentiality, integrity, and availability of SGX-protected applications, making it particularly dangerous in environments where secure remote attestation is critical for system integrity.
The vulnerability aligns with CWE-276, which addresses improper file permissions and inadequate access control mechanisms. From an adversarial perspective, this weakness maps to ATT&CK technique T1068, which involves the exploitation of local privilege escalation opportunities. Attackers can leverage this vulnerability to establish persistent denial of service conditions that prevent legitimate system operations from functioning properly, effectively creating a backdoor that can be used to maintain long-term access to compromised systems.
Mitigation strategies should focus on immediate patch deployment to version 2.1.102 or later, which addresses the core validation issues within the AESM daemon. System administrators should also implement additional monitoring controls to detect unauthorized file system modifications in the daemon's operational directories. Network segmentation and privilege separation measures can help limit the potential impact of local compromise, while regular security audits should verify that proper file permissions and access controls are maintained. The vulnerability underscores the importance of robust input validation and access control mechanisms in security-critical system components, particularly those involved in attestation and trust establishment processes.