LibVNC Client null pointer dereference

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-$5k0.00

A vulnerability classified as problematic has been found in LibVNC (the affected version unknown). Affected is an unknown part of the component Client. The manipulation with an unknown input 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:

LibVNC before commit 4a21bbd097ef7c44bb000c3bd0907f96a10e4ce7 contains null pointer dereference in VNC client code that can result DoS.

The bug was discovered 12/19/2018. The weakness was shared 12/19/2018 by Solar Designer (Website). The advisory is shared for download at ics-cert.kaspersky.com. This vulnerability is traded as CVE-2018-20024 since 12/10/2018. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 119877 (Debian DLA-1617-1 : libvncserver security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 171837 (SUSE Enterprise Linux Security Update for LibVNCServer (SUSE-SU-2019:0060-1)).

Applying the patch 4a21bbd097ef7c44bb000c3bd0907f96a10e4ce7 is able to eliminate this problem. A possible mitigation has been published 1 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (119877) and SecurityFocus (BID 106825†). The entries VDB-128103, VDB-128104, VDB-128119 and VDB-128120 are related to this item.

Productinfo

Name

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

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
unlockunlockunlockunlockunlockunlock
unlockunlockunlockunlockunlockunlock
unlockunlockunlockunlockunlockunlock

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-Dayunlockunlockunlockunlock
Todayunlockunlockunlockunlock

Nessus ID: 119877
Nessus Name: Debian DLA-1617-1 : libvncserver security update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

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

Patch: 4a21bbd097ef7c44bb000c3bd0907f96a10e4ce7

Timelineinfo

12/10/2018 🔍
12/19/2018 +9 days 🔍
12/19/2018 +0 days 🔍
12/19/2018 +0 days 🔍
12/20/2018 +1 days 🔍
12/26/2018 +6 days 🔍
12/27/2018 +1 days 🔍
01/31/2019 +35 days 🔍
06/20/2023 +1601 days 🔍

Sourcesinfo

Advisory: USN-3877-1
Researcher: Solar Designer
Status: Confirmed

CVE: CVE-2018-20024 (🔍)
SecurityFocus: 106825 - LibVNCServer Incomplete Fix Multiple Heap Buffer Overflow Vulnerabilities

See also: 🔍

Entryinfo

Created: 12/20/2018 07:50 AM
Updated: 06/20/2023 06:52 AM
Changes: 12/20/2018 07:50 AM (72), 04/22/2020 09:08 AM (5), 06/20/2023 06:52 AM (4)
Complete: 🔍
Cache ID: 18:879:40

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Might our Artificial Intelligence support you?

Check our Alexa App!