CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.00

A vulnerability, which was classified as problematic, was found in Heimdal 7.4. Affected is the function der_length_visible_string in the library lib/asn1/der_length.c of the file kdc/kerberos5.c of the component KDC. The manipulation as part of a UDP Packet leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

In Heimdal 7.1.0, 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.

The bug was discovered 10/10/2017. The weakness was presented 12/06/2017 (Website). The advisory is available at bugs.debian.org. This vulnerability is traded as CVE-2017-17439 since 12/06/2017. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit.

The vulnerability was handled as a non-public zero-day exploit for at least 57 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 105244 (openSUSE Security Update : libheimdal (openSUSE-2017-1364)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 171517 (OpenSUSE Security Update for libheimdal (openSUSE-SU-2018:2376-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 6 days after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (105244).

Productinfo

Name

• Heimdal

Version

• 7.4

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Nessus ID: 105244
Nessus Name: openSUSE Security Update : libheimdal (openSUSE-2017-1364)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 840645
OpenVAS Name: Debian Security Advisory DSA 4055-1 (heimdal - security update)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Patch: github.com

Timelineinfo

10/10/2017 🔍
12/06/2017 +57 days 🔍
12/06/2017 +0 days 🔍
12/06/2017 +0 days 🔍
12/06/2017 +0 days 🔍
12/12/2017 +6 days 🔍
12/14/2017 +2 days 🔍
01/17/2023 +1860 days 🔍

Sourcesinfo

Advisory: 1a6a6e462dc2ac6111f9e02c6852ddec4849b887
Status: Not defined
Confirmation: 🔍

CVE: CVE-2017-17439 (🔍)
OVAL: 🔍

Entryinfo

Created: 12/06/2017 22:13
Updated: 01/17/2023 08:51
Changes: 12/06/2017 22:13 (75), 12/12/2019 15:34 (4), 01/17/2023 08:51 (5)
Complete: 🔍

Discussion

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