Red Hat Enterprise Linux 8 update for gnutls and nettle

1) Use of a broken or risky cryptographic algorithm

EUVDB-ID: #VU52195

Risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20305

CWE-ID: CWE-327 - Use of a Broken or Risky Cryptographic Algorithm

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) result in the Elliptic Curve Cryptography point (ECC) multiply function being called with out-of-range scalers, possibly resulting in incorrect results. This flaw allows an attacker to force an invalid signature, causing an assertion failure or possible validation. The highest threat to this vulnerability is to confidentiality, integrity, as well as system availability.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

gnutls (Red Hat package): 3.6.14-7.el8_3

Red Hat Enterprise Linux for ARM 64: 8

Red Hat Enterprise Linux for Power, little endian: 8

Red Hat Enterprise Linux for IBM z Systems: 8

Red Hat Enterprise Linux for x86_64: 8.0

nettle (Red Hat package): before 3.4.1-4.el8_3

External links

http://access.redhat.com/errata/RHSA-2021:1206

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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