CVE-2017-17439

Severity Score

7.5

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

En Heimdal hasta la versión 7.4 atacantes remotos no autenticados pueden provocar el cierre inesperado del KDC enviando un paquete UDP manipulado que contenga campos de datos vacíos para el nombre del cliente o para el realm. En ese caso, el analizador sintáctico desreferenciará punteros NULL incondicionalmente, lo que dará lugar a un fallo de segmentación. Esto está relacionado con la función _kdc_as_rep en kdc/kerberos5.c y la función der_length_visible_string function en lib/asn1/der_length.c.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2017-12-06 CVE Reserved
2017-12-06 CVE Published
2024-08-05 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-476: NULL Pointer Dereference

CAPEC

References (7)

URL	Tag	Source
http://h5l.org/advisories.html?show=2017-12-08	X_refsource_confirm
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html	X_refsource_confirm
http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html	Third Party Advisory
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144	Issue Tracking
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://github.com/heimdal/heimdal/issues/353	2017-12-30

URL	Date	SRC
https://www.debian.org/security/2017/dsa-4055	2017-12-30

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Heimdal Project Search vendor "Heimdal Project"		Heimdal Search vendor "Heimdal Project" for product "Heimdal"				<= 7.4.0 Search vendor "Heimdal Project" for product "Heimdal" and version " <= 7.4.0"		-		Affected