LibVNC up to 0.9.11 libvncclient/rfbproto.c out-of-bounds write

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.
8.4$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in LibVNC up to 0.9.11. This impacts an unknown function of the file libvncclient/rfbproto.c. The manipulation leads to out-of-bounds write. This vulnerability is uniquely identified as CVE-2018-20748. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in LibVNC up to 0.9.11. It has been rated as critical. This issue affects an unknown code of the file libvncclient/rfbproto.c. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete.

The bug was discovered 12/10/2018. The weakness was disclosed 01/30/2019 by Solar Designer (Website). The advisory is shared at github.com. The identification of this vulnerability is CVE-2018-20748 since 01/30/2019. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 51 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 121517 (Debian DLA-1652-1 : 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 197361 (Ubuntu Security Notification for Libvncserver Vulnerabilities (USN-3877-1)).

Upgrading to version 0.9.12 eliminates this vulnerability. A possible mitigation has been published 1 days after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (121517) and SecurityFocus (BID 106825†). The entries VDB-128103, VDB-128104, VDB-128119 and VDB-128120 are pretty similar. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

NVD Base Score: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 121517
Nessus Name: Debian DLA-1652-1 : 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: Upgrade
Status: 🔍

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

Upgrade: LibVNC 0.9.12
Patch: github.com

Timelineinfo

12/10/2018 🔍
01/30/2019 +51 days 🔍
01/30/2019 +0 days 🔍
01/30/2019 +0 days 🔍
01/31/2019 +1 days 🔍
01/31/2019 +0 days 🔍
01/31/2019 +0 days 🔍
02/01/2019 +1 days 🔍
07/04/2023 +1614 days 🔍

Sourcesinfo

Advisory: DLA 1617-1
Researcher: Solar Designer
Status: Confirmed

CVE: CVE-2018-20748 (🔍)
GCVE (CVE): GCVE-0-2018-20748
GCVE (VulDB): GCVE-100-130337
SecurityFocus: 106825 - LibVNCServer Incomplete Fix Multiple Heap Buffer Overflow Vulnerabilities

See also: 🔍

Entryinfo

Created: 01/31/2019 13:05
Updated: 07/04/2023 08:36
Changes: 01/31/2019 13:05 (74), 05/06/2020 20:28 (5), 07/04/2023 08:34 (5), 07/04/2023 08:35 (1), 07/04/2023 08:36 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Are you interested in using VulDB?

Download the whitepaper to learn more about our service!