CVE-2017-17439 : In Heimdal through 7.4, remote unauthenticated attackers are able to crash the K

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.

Published 2017-12-06 15:29:00

Updated 2017-12-30 02:29:02

Source MITRE

View at NVD, CVE.org

Vulnerability category: Memory Corruption

Products affected by CVE-2017-17439

Debian » Debian Linux » Version: 9.0
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
Matching versions
Heimdal Project » Heimdal
Versions up to, including, (<=) 7.4.0
cpe:2.3:a:heimdal_project:heimdal:*:*:*:*:*:*:*:*
Matching versions

Exploit prediction scoring system (EPSS) score for CVE-2017-17439

EPSS FAQ

66.03%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 97 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2017-17439

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
5.0	MEDIUM	AV:N/AC:L/Au:N/C:N/I:N/A:P	10.0	2.9	NIST
Access Vector: Network Access Complexity: Low Authentication: None Confidentiality Impact: None Integrity Impact: None Availability Impact: Partial
7.5	HIGH	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	3.9	3.6	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Unchanged Confidentiality: None Integrity: None Availability: High

CWE ids for CVE-2017-17439

CWE-476 NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2017-17439

http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html

Segfaults after receiving invalid AS-REQ
Third Party Advisory
https://www.debian.org/security/2017/dsa-4055

Debian -- Security Information -- DSA-4055-1 heimdal
Third Party Advisory
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887

Security: Avoid NULL structure pointer member dereference · heimdal/heimdal@1a6a6e4 · GitHub
Third Party Advisory
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html

[Heimdal-announce] Heimdal 7.5 security release announcement.
https://github.com/heimdal/heimdal/issues/353

Remote unauthenticated DoS in Heimdal-KDC 7.1 · Issue #353 · heimdal/heimdal · GitHub
Patch;Third Party Advisory
http://h5l.org/advisories.html?show=2017-12-08

Heimdal security advisories
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144

#878144 - CVE-2017-17439: Remote unauthenticated DoS in Heimdal-KDC 7.1 - Debian Bug report logs
Issue Tracking;Mailing List;Third Party Advisory

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Vulnerability Details : CVE-2017-17439

Products affected by CVE-2017-17439

Exploit prediction scoring system (EPSS) score for CVE-2017-17439

CVSS scores for CVE-2017-17439

CWE ids for CVE-2017-17439

References for CVE-2017-17439