CVE-2019-14870

NameCVE-2019-14870
DescriptionAll Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the S4U (MS-SFU) Kerberos delegation model includes a feature allowing for a subset of clients to be opted out of constrained delegation in any way, either S4U2Self or regular Kerberos authentication, by forcing all tickets for these clients to be non-forwardable. In AD this is implemented by a user attribute delegation_not_allowed (aka not-delegated), which translates to disallow-forwardable. However the Samba AD DC does not do that for S4U2Self and does set the forwardable flag even if the impersonated client has the not-delegated flag set.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium
Debian Bugs946786

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
heimdal (PTS)jessie (security), jessie1.6~rc2+dfsg-9+deb8u1vulnerable
stretch (security), stretch7.1.0+dfsg-13+deb9u3vulnerable
buster7.5.0+dfsg-3vulnerable
bullseye, sid7.7.0+dfsg-1fixed
samba (PTS)jessie2:4.2.14+dfsg-0+deb8u9vulnerable
jessie (security)2:4.2.14+dfsg-0+deb8u13vulnerable
stretch (security), stretch2:4.5.16+dfsg-1+deb9u2vulnerable
buster2:4.9.5+dfsg-5vulnerable
buster (security)2:4.9.5+dfsg-5+deb10u1vulnerable
bullseye, sid2:4.11.5+dfsg-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
heimdalsource(unstable)7.7.0+dfsg-1946786
sambasource(unstable)2:4.11.3+dfsg-1

Notes

[buster] - samba <no-dsa> (Minor issue)
[stretch] - samba <no-dsa> (Minor issue)
[jessie] - samba <no-dsa> (Minor issue)
[buster] - heimdal <no-dsa> (Minor issue)
[stretch] - heimdal <no-dsa> (Minor issue)
[jessie] - heimdal <no-dsa> (Minor issue)
https://www.samba.org/samba/security/CVE-2019-14870.html
https://github.com/heimdal/heimdal/pull/663
https://github.com/heimdal/heimdal/pull/664 (port to 7.1 branch)

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