CVE-2018-21029
Description
A flaw in systemd-resolved was found to incorrectly verify certificates of a DNS resolver used for DNS Over TLS when the DNSOverTLS option is set to yes. A remote attacker in the network path between the vulnerable system and the DNS resolver may use this flaw to perform a man-in-the-middle attack and eavesdrop or modify DNS queries and responses. The attacker can learn the sites visited by a victim user, or redirect the victim user to malicious sites.
Statement
Versions of systemd as shipped with Red Hat Enterprise Linux 7 are not affected by this issue as they did not include support for DNSOverTLS option.
Versions of systemd as shipped with Red Hat Enterprise Linux 8 are not affected by this issue as they did not support the yes value of the DNSOverTLS option.
OpenShift Container Platform 4.1 ships a version of systemd from Red Hat Enterprise Linux 8 and is thus also not affected by this issue.
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 | 6.3 | 9.8 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | High | N/A |
| Integrity Impact | Low | High | N/A |
| Availability Impact | Low | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Authentication
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The product might connect to a malicious host while believing it is a trusted host, or the product might be deceived into accepting spoofed data that appears to originate from a trusted host.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
