CVE-2018-21029
CRITICAL severity · CVSS 9.8 · CWE-295
9.8CVSS CRITICAL
Summary
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)
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)3%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products we track (1)
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Official patch: https://github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c#L62-L63 ↗
Additional information
- NVD record
- https://github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c#L62-L63Patch
- https://github.com/systemd/systemd/pull/13870Patch
- https://blog.cloudflare.com/dns-encryption-explained/Advisory
- https://github.com/systemd/systemd/issues/9397Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
- https://security.netapp.com/advisory/ntap-20191122-0002/Advisory
- https://github.com/systemd/systemd/blob/v239/man/resolved.conf.xml#L199-L207Advisory
- https://github.com/systemd/systemd/blob/v243/man/resolved.conf.xml#L196-L207Advisory