Release Notes - Heimdal - Version Heimdal 7.6
CVE-2018-16860 Heimdal KDC: Reject PA-S4U2Self with unkeyed checksum
When the Heimdal KDC checks the checksum that is placed on the
S4U2Self packet by the server to protect the requested principal
against modification, it does not confirm that the checksum
algorithm that protects the user name (principal) in the request
is keyed. This allows a man-in-the-middle attacker who can
intercept the request to the KDC to modify the packet by replacing
the user name (principal) in the request with any desired user
name (principal) that exists in the KDC and replace the checksum
protecting that name with a CRC32 checksum (which requires no
prior knowledge to compute).
This would allow a S4U2Self ticket requested on behalf of user
name (principal) user@EXAMPLE.COM to any service to be changed
to a S4U2Self ticket with a user name (principal) of
Administrator@EXAMPLE.COM. This ticket would then contain the
PAC of the modified user name (principal).
RFC8062 Section 7 requires verification of the PA-PKINIT-KX key exchange
when anonymous PKINIT is used. Failure to do so can permit an active
attacker to become a man-in-the-middle.
- Happy eyeballs: Don't wait for responses from known-unreachable KDCs.
- kdc: check return copy_Realm, copy_PrincipalName, copy_EncryptionKey
. cleanup temporary ccaches
. see man page for "kinit --anonymous" command line syntax change
- kdc: Make anonymous AS-requests more RFC8062-compliant.
- Updated expired test certificates
. PKCS#11 hcrypto backend broken since 7.0.1
. Building with Sun Pro C
- kuser: support authenticated anonymous AS-REQs in kinit
- kdc: support for anonymous TGS-REQs
- kgetcred support for anonymous service tickets
- Support builds with OpenSSL 1.1.1
Building from source:
heimdal-7.6.0.tar.gz and its matching PGP signature file (heimdal-7.6.0.tar.gz) should be downloaded in preference to the GitHub generated "source" archives. The heimdal-7.6.0.tar.gz archive contains the required build products necessary to "configure" and "make".
The GitHub generated "source" archives contain a raw copy of the repository contents for the "heimdal-7.6.0" tag.