openSUSE Security Update: Security update for libheimdal
______________________________________________________________________________
Announcement ID: openSUSE-SU-2019:1888-1
Rating: moderate
References: #1047218 #1084909
Cross-References: CVE-2018-16860 CVE-2019-12098
Affected Products:
openSUSE Backports SLE-15-SP1
______________________________________________________________________________
An update that fixes two vulnerabilities is now available.
Description:
This update for libheimdal fixes the following issues:
libheimdal was updated to version 7.7.0:
+ Bug fixes:
– PKCS#11 hcrypto back-end:
+ initialize the p11_module_load function list
+ verify that not only is a mechanism present but that its mechanism
info states that it offers the required encryption, decryption or
digest services
– krb5:
+ Starting with 7.6, Heimdal permitted requesting authenticated
anonymous tickets. However, it did not verify that a KDC in fact
returned an anonymous ticket when one was requested.
+ Cease setting the KDCOption reaquest_anonymous flag when issuing
S4UProxy (constrained delegation) TGS requests.
+ when the Win2K PKINIT compatibility option is set, do not require
krbtgt otherName to match when validating KDC certificate.
+ set PKINIT_BTMM flag per Apple implementation
+ use memset_s() instead of memset()
– kdc:
+ When generating KRB5SignedPath in the AS, use the reply client name
rather than the one from the request, so validation will work
correctly in the TGS.
+ allow checksum of PA-FOR-USER to be HMAC_MD5. Even if TGT used an
enctype with a different checksum. Per [MS-SFU] 2.2.1 PA-FOR-USER
the checksum is always HMAC_MD5, and that’s what Windows and MIT
clients send. In Heimdal both the client and kdc use instead the
checksum of the TGT, and therefore work with each other but Windows
and MIT clients fail against Heimdal KDC. Both Windows and MIT KDC
would allow any keyed checksum to be used so Heimdal client work
fine against it. Change Heimdal KDC to allow HMAC_MD5 even for non
RC4 based TGT in order to support per-spec clients.
+ use memset_s() instead of memset()
+ Detect Heimdal 1.0 through 7.6 clients that issue S4UProxy
(constrained delegation) TGS Requests with the request anonymous
flag set. These requests will be treated as S4UProxy requests and
not anonymous requests.
– HDB:
+ Set SQLite3 backend default page size to 8KB.
+ Add hdb_set_sync() method
– kadmind:
+ disable HDB sync during database load avoiding unnecessary disk i/o.
– ipropd:
+ disable HDB sync during receive_everything. Doing an fsync
per-record when receiving the complete HDB is a performance
disaster. Among other things, if the HDB is very large, then one
slave receving a full HDB can cause
other slaves to timeout and, if HDB write activity is high enough to
cause iprop log truncation, then also need full syncs, which leads to a
cycle of full syncs for all slaves until HDB write activity drops.
Allowing the iprop log to be larger helps, but improving
receive_everything() performance helps even more.
– kinit:
+ Anonymous PKINIT tickets discard the realm information used to
locate the issuing AS. Store the issuing realm in the credentials
cache in order to locate a KDC which can renew them.
+ Do not leak the result of krb5_cc_get_config() when determining
anonymous PKINIT start realm.
– klist:
+ Show transited-policy-checked, ok-as-delegate and anonymous flags
when listing credentials.
– tests:
+ Regenerate certs so that they expire before the 2038 armageddon so
the test suite will pass on 32-bit
operating systems until the underlying issues can be resolved.
– documentation:
+ rename verify-password to verify-password-quality
+ hprop default mode is encrypt
+ kadmind “all” permission does not include “get-keys”
+ verify-password-quality might not be stateless
Version 7.6.0:
+ Security (#555):
– 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).
– CVE-2019-12098, client-only:
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.
+ Bug fixes:
– Happy eyeballs: Don’t wait for responses from known-unreachable KDCs.
– kdc:
+ check return copy_Realm, copy_PrincipalName, copy_EncryptionKey
– kinit:
+ 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
+ Features:
– 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
This update was imported from the openSUSE:Leap:15.0:Update update project.
Patch Instructions:
To install this openSUSE Security Update use the SUSE recommended installation methods
like YaST online_update or “zypper patch”.
Alternatively you can run the command listed for your product:
– openSUSE Backports SLE-15-SP1:
zypper in -t patch openSUSE-2019-1888=1
Package List:
– openSUSE Backports SLE-15-SP1 (aarch64 ppc64le s390x x86_64):
libheimdal-7.7.0-bp151.4.3.1
libheimdal-devel-7.7.0-bp151.4.3.1
References:
https://www.suse.com/security/cve/CVE-2018-16860.html
https://www.suse.com/security/cve/CVE-2019-12098.html
https://bugzilla.suse.com/1047218
https://bugzilla.suse.com/1084909
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