CVE-2020-1968
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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.
Additional information
- Bugzilla 1877458: openssl: Information exposure when DH secret are reused across multiple TLS connections
- CWE-385->CWE-200: Covert Timing Channel leads to Exposure of Sensitive Information to an Unauthorized Actor
- FAQ: Frequently asked questions about CVE-2020-1968
Common Vulnerability Scoring System (CVSS) Score Details
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.
Red Hat | NVD | |
---|---|---|
CVSS v3 Base Score | 5.9 | 3.7 |
Attack Vector | Network | Network |
Attack Complexity | High | High |
Privileges Required | None | None |
User Interaction | None | None |
Scope | Unchanged | Unchanged |
Confidentiality Impact | High | Low |
Integrity Impact | None | None |
Availability Impact | None | None |
CVSS v3 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
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- The term "Affected" means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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