Ciphertext side channel attack in AMD EPYC processors

1) Cryptographic issues

EUVDB-ID: #VU63692

Risk: Low

CVSSv3.1: 3.1 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:U/RC:C]

CVE-ID: CVE-2021-46744

CWE-ID: CWE-310 - Cryptographic Issues

Exploit availability: No

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to a ciphertext side channel attack where data in specific cryptographic algorithms can be inferred in a SEV guest by monitoring the ciphertext values over time. A local user with access to the hypervisor can gain access to sensitive information, related to the guest OS.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

1st Gen AMD EPYC Processors: All versions

2nd Gen AMD EPYC Processors: All versions

3rd Gen AMD EPYC Processors: All versions

AMD EPYC Embedded Processors: All versions

External links

http://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1033
http://www.amd.com/system/files/documents/221404394-a_security_wp_final.pdf

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.