High severity · published Dec 6, 2017
CVE-2017-17439
In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm
7.5
CVSS
3.4%
EPSS
No
On KEV
Description
In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.4% · higher than 89% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DL
Debian Linux · Debian
9.0 · source: NVD
HE
Heimdal · Heimdal Project
through 7.4.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-17439
CVE.org
https://www.cve.org/CVERecord?id=CVE-2017-17439
h5l.org
http://h5l.org/advisories.html?show=2017-12-08
www.h5l.org
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html
Third Party Advisory
http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html
Issue Tracking
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144
Third Party Advisory
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887
Patch
https://github.com/heimdal/heimdal/issues/353
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