VNC RealVNC 4.1.1 improper authentication

CVSS Meta Temp Score
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CTI Interest Score
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7.1$0-$5k0.00

Summaryinfo

A vulnerability has been found in VNC RealVNC 4.1.1 and classified as problematic. This issue affects some unknown processing. Performing a manipulation results in improper authentication. This vulnerability was named CVE-2006-2369. In addition, an exploit is available. It is suggested to enhance authentication.

Detailsinfo

A vulnerability, which was classified as critical, was found in VNC RealVNC 4.1.1. This affects an unknown part. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

RealVNC 4.1.1, and other products that use RealVNC such as AdderLink IP and Cisco CallManager, allows remote attackers to bypass authentication via a request in which the client specifies an insecure security type such as "Type 1 - None", which is accepted even if it is not offered by the server, as originally demonstrated using a long password.

The bug was discovered 05/08/2006. The weakness was presented 05/15/2006 by Steve Wiseman as confirmed advisory (CERT.org). It is possible to read the advisory at kb.cert.org. This vulnerability is uniquely identified as CVE-2006-2369 since 05/15/2006. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are unknown but a public exploit is available.

After even before and not, there has been an exploit disclosed. The exploit is shared for download at immunitysec.com. It is declared as highly functional. The vulnerability was handled as a non-public zero-day exploit for at least 7 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 21574 (FreeBSD : vnc -- authentication bypass vulnerability (4645b98c-e46e-11da-9ae7-00123fcc6e5c)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family FreeBSD Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 38545 (RealVNC Password Authentication Bypass Vulnerability).

It is possible to mitigate the problem by adding an authentication mechanism. A possible mitigation has been published 3 days after the disclosure of the vulnerability. Attack attempts may be identified with Snort ID 6471. Furthermore it is possible to detect and prevent this kind of attack with TippingPoint and the filter 4410.

The vulnerability is also documented in the databases at X-Force (26445), Exploit-DB (1791), Tenable (21574), SecurityFocus (BID 17978†) and OSVDB (25479†). See VDB-82, VDB-332, VDB-333 and VDB-427 for similar entries. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.3
VulDB Temp Score: 7.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Highly functional
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 21574
Nessus Name: FreeBSD : vnc -- authentication bypass vulnerability (4645b98c-e46e-11da-9ae7-00123fcc6e5c)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

OpenVAS ID: 56775
OpenVAS Name: FreeBSD Ports: vnc
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

MetaSploit ID: realvnc_41_bypass.rb
MetaSploit Name: RealVNC NULL Authentication Mode Bypass
MetaSploit File: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Authentication
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Snort ID: 6471

Suricata ID: 2002912
Suricata Class: 🔍
Suricata Message: 🔍

TippingPoint: 🔍

McAfee IPS: 🔍
McAfee IPS Version: 🔍

SourceFire IPS: 🔍
ISS Proventia IPS: 🔍
PaloAlto IPS: 🔍
Fortigate IPS: 🔍

Timelineinfo

05/08/2006 🔍
05/12/2006 +4 days 🔍
05/15/2006 +3 days 🔍
05/15/2006 +0 days 🔍
05/15/2006 +0 days 🔍
05/15/2006 +0 days 🔍
05/15/2006 +0 days 🔍
05/15/2006 +0 days 🔍
05/15/2006 +0 days 🔍
05/18/2006 +2 days 🔍
05/19/2006 +1 days 🔍
05/22/2006 +3 days 🔍
03/12/2015 +3216 days 🔍
06/22/2025 +3755 days 🔍

Sourcesinfo

Advisory: kb.cert.org
Researcher: Steve Wiseman
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2006-2369 (🔍)
GCVE (CVE): GCVE-0-2006-2369
GCVE (VulDB): GCVE-100-30243

IAVM: 🔍

CERT: 🔍
X-Force: 26445
SecurityFocus: 17978 - RealVNC Remote Authentication Bypass Vulnerability
Secunia: 20109
OSVDB: 25479 - RealVNC Security Type Enforcement Failure Remote Authentication Bypass
SecurityTracker: 1016083
Vulnerability Center: 11491 - [cisco-sr-20060622-cmm] RealVNC Authentication Bypass via Unoffered Insecure Connection, High
Vupen: ADV-2006-1790

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 03/12/2015 12:19
Updated: 06/22/2025 02:15
Changes: 03/12/2015 12:19 (100), 06/18/2019 10:37 (9), 01/20/2025 08:13 (17), 06/22/2025 02:15 (2)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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