CVE-2025-20613 is a vulnerability identified in the firmware of certain Intel(R) Trusted Domain Extensions (TDX) implementations. The core issue stems from the use of a predictable seed in the pseudo-random number generator (PRNG) within the firmware. PRNGs are critical components for generating cryptographic keys, nonces, and other security parameters. When the seed used to initialize the PRNG is predictable, it significantly weakens the randomness and thus the security guarantees of cryptographic operations relying on it. In this case, the predictable seed can be exploited by an authenticated user with local access to the system to potentially cause information disclosure. This means that sensitive data processed or stored within the TDX environment could be exposed to unauthorized parties. Intel TDX is designed to provide hardware-based isolation for virtual machines, enhancing security in cloud and multi-tenant environments by protecting workloads from other software, including the host OS and hypervisor. A weakness in the PRNG undermines this isolation by potentially allowing leakage of confidential information. The vulnerability requires local access and low privileges (authenticated user with local access), and does not require user interaction. The CVSS 4.0 base score is 2.0, indicating a low severity primarily due to limited impact scope and the requirement for local authenticated access. There are no known exploits in the wild, and no patches or mitigations have been explicitly linked in the provided information. The vulnerability does not affect confidentiality, integrity, or availability broadly but specifically targets confidentiality through information disclosure. The predictable seed issue is a firmware-level flaw, which may require firmware updates or microcode patches from Intel to fully remediate. Until such patches are available, risk mitigation relies on limiting local access and monitoring for suspicious activity within environments using Intel TDX.

For European organizations, especially those leveraging Intel TDX technology in cloud infrastructure or virtualized environments, this vulnerability poses a risk of sensitive data leakage within isolated virtual machines. Organizations in sectors such as finance, healthcare, and government, which often handle highly sensitive information and increasingly adopt confidential computing technologies like TDX, could see confidentiality compromised if an attacker gains local authenticated access. Although the vulnerability requires local access and low privileges, insider threats or attackers who have already compromised user accounts could exploit this to escalate data exposure. The impact is somewhat limited by the low CVSS score and the absence of known exploits, but the potential for information disclosure in trusted execution environments undermines the security assurances that TDX aims to provide. This could erode trust in confidential computing deployments and complicate compliance with stringent European data protection regulations like GDPR, which mandate strong data confidentiality controls. Additionally, organizations relying on multi-tenant cloud services that utilize Intel TDX may face increased risk if cloud providers do not promptly address this vulnerability. Overall, while the immediate risk is low, the strategic importance of TDX in securing sensitive workloads means European organizations should proactively address this vulnerability to maintain data confidentiality and regulatory compliance.

1. Restrict local access: Limit the number of users with authenticated local access to systems running Intel TDX to reduce the attack surface. 2. Monitor and audit: Implement enhanced monitoring and auditing of local user activities on TDX-enabled systems to detect any suspicious behavior indicative of exploitation attempts. 3. Firmware updates: Stay in close contact with Intel for firmware or microcode updates addressing this vulnerability and apply patches promptly once available. 4. Isolate sensitive workloads: Where possible, segregate highly sensitive workloads into environments with stricter access controls and additional layers of security beyond TDX. 5. Use complementary security controls: Employ additional encryption and data protection mechanisms at the application or OS level to mitigate potential information disclosure risks from firmware vulnerabilities. 6. Vendor engagement: Engage with cloud service providers or hardware vendors to confirm their mitigation plans and timelines for this vulnerability in their Intel TDX deployments. 7. Incident response readiness: Prepare incident response plans that include scenarios involving local authenticated attackers exploiting firmware weaknesses to ensure rapid containment and remediation.