CVE-2020-1968
Description
A flaw was found in openssl in versions 1.0.2 to 1.0.2w. A Raccoon attack exploits a flaw in the TLS specification which can lead to an attacker being able to compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite. In such a case this would result in the attacker being able to eavesdrop on all encrypted communications sent over that TLS connection. The highest threat from this vulnerability is to data confidentiality.
Statement
openssl 1.1.0i as bundled in the ovmf package shipped with Red Hat Enterprise Linux 7 supplementary rpms is not affected by this flaw. openssl 1.1.1 as shipped in Red Hat Enterprise Linux 8 is also not affected.
Red Hat Advanced Cluster Management for Kubernetes does not use the vulnerable cipher suites, so it is not impacted by this flaw.
Mitigation
In OpenSSL 1.0.2e and below, this flaw can be mitigated by not enabling any ciphersuites with Diffie Hellman (DH), excluding ciphersuites using Elliptic Curve Diffie Hellman (ECDH).
In OpenSSL 1.0.2f and above, this flaw can be mitigated by not enabling static DH ciphersuites. Such ciphersuites start with `DH-` in OpenSSL and are mapped to IANA names that start with `TLS_DH_`, excluding ciphersuites that start with `TLS_DH_anon`. Following this convention, we see that `DH-RSA-AES256-GCM-SHA384` with IANA name `TLS_DH_RSA_WITH_AES_256_GCM_SHA384` is affected and should not be used in a mitigation of this flaw. However, `ECDH-RSA-AES128-GCM-SHA256` with IANA name `TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256` is not affected and may be used in a mitigation to this flaw, as it does not follow the `DH-` or `TLS_DH_` naming convention.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | 3.7 | 3.7 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | High | High |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | Low | Low |
| Integrity Impact | None | None | None |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
Potentially a replay attack, in which an attacker could send the same data twice, could be crafted if nonces are allowed to be reused. This could allow a user to send a message which masquerades as a valid message from a valid user.
Frequently Asked Questions
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