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Ultr@VNC Buffer Overflow Vulnerabilities
Secunia Advisory: SA19513
Release Date: 2006-04-05
Last Update: 2006-07-03
Popularity: 8,505 views

Critical:
Moderately critical
Impact: DoS
System access
Where: From remote
Solution Status: Vendor Patch

Software:UltraVNC (formerly Ultr@VNC) 1.x

Secunia CVSS-2 Score: Available in Secunia business solutions

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Advisory Content (Page 1 of 3)[ 1 ] [ 2 ] [ 3 ]

Description:
Luigi Auriemma has reported two vulnerabilities in Ultr@VNC, which can be exploited by malicious people to cause a DoS (Denial of Service) and potentially compromise a vulnerable system.

1) A boundary error exists in the "Log::ReallyPrint()" client function when logging replies received from a VNC server during login. This can be exploited to cause a buffer overflow on a client system via a "connection failed" error response with an overly long string.

Successful exploitation may allow execution of arbitrary code on a client system when e.g. connecting to a malicious VNC server.

2) A boundary error in the "VNCLog::ReallyPrint()" function when logging information can be exploited to cause a buffer overflow. This may crash the VNC service or allow execution of arbitrary code.

Successful exploitation requires that an administrative user has changed the default "Log debug infos to the WinVNC.log file" setting in the configuration. Systems are still vulnerable even when this setting has been changed back to the default state.

The vulnerabilities have been reported in version 1.0.1. Other versions may also be affected.

Change Page:
[ 1 ] [ 2 ] [ 3 ]



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