Remote Denial of Service Vulnerability in Heimdal KDC

CVE-2017-17439 · MEDIUM Severity

AV:N/AC:L/AU:N/C:N/I:N/A:P

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.

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