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. 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.

Bugs

• <https://github.com/heimdal/heimdal/issues/353&gt;
• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144&gt;

Notes