CVE-2018-21029
First published: Wed Oct 30 2019(Updated: )
** DISPUTED ** systemd 239 through 245 accepts any certificate signed by a trusted certificate authority for DNS Over TLS. Server Name Indication (SNI) is not sent, and there is no hostname validation with the GnuTLS backend. NOTE: This has been disputed by the developer as not a vulnerability since hostname validation does not have anything to do with this issue (i.e. there is no hostname to be sent).
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Systemd Project Systemd | >=239<244 | |
| Fedoraproject Fedora | =31 | |
| >=239<244 | ||
| =31 |
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Reference Links
- https://blog.cloudflare.com/dns-encryption-explained/
- https://github.com/systemd/systemd/blob/v239/man/resolved.conf.xml#L199-L207
- https://github.com/systemd/systemd/blob/v243/man/resolved.conf.xml#L196-L207
- https://github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c#L62-L63
- https://github.com/systemd/systemd/issues/9397
- https://github.com/systemd/systemd/pull/13870
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
- https://security.netapp.com/advisory/ntap-20191122-0002/
- https://tools.ietf.org/html/rfc7858#section-4.1
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
Frequently Asked Questions
What is CVE-2018-21029?
CVE-2018-21029 is a vulnerability in systemd versions 239 through 245 that allows the acceptance of any certificate signed by a trusted certificate authority for DNS Over TLS without proper hostname validation.
Is CVE-2018-21029 a critical vulnerability?
Yes, CVE-2018-21029 has a severity keyword of 'critical' and a severity value of 9.8.
How does CVE-2018-21029 affect systemd?
CVE-2018-21029 affects systemd versions 239 through 245 and allows the acceptance of any certificate signed by a trusted certificate authority for DNS Over TLS without proper hostname validation.
What is the impact of CVE-2018-21029?
The impact of CVE-2018-21029 is that an attacker could use a malicious certificate to perform man-in-the-middle attacks on DNS traffic.
How can CVE-2018-21029 be mitigated?
To mitigate CVE-2018-21029, it is recommended to update systemd to a version that includes the fix for the vulnerability.
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