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[123Privacy] Findnot.com DNS Privacy Breach, DNS Spoofing Exposure, and ISP Monitoring Vulnerability
From: "123 Privacy Advisories" <123privacy_advisory () mailvault com>
Date: Thu, 20 Apr 2006 04:02:54 00200 (CEST)

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Findnot.com DNS Privacy Breach, DNS Spoofing Exposure, and ISP
Monitoring Vulnerability

Advisory ID:    FN15398

Release Date:   2006-04-18

Last Update:    2006-04-18

Severity:       Critical

IMPACT:
        
Website locations visited are viewable by users on local wireless
connection, local network, and ISP. User is exposed to possible
local/ISP DNS spoofing. Internet sites accessed easily monitored by ISP
operating DNS server.

Where:          From localnetwork, and from remote servers.

Solution Status:        Unpatched

Software:       Findnot.com's SSH Proxy Service.

Related Advisories:     FN15294

DESCRIPTION:

Several vulnerabilities have been reported in Findnot.com's SSH Proxy
Service which can cause all DNS requests for lookup of sites visited to
be resolved using local DNS servers.

* Exposing the location of all sites visited to local wireless, network,
sysadmin snoopers or to an ISP that is monitoring their DNS server.

* A local attacker may also spoof a DNS request and send the user to a
site specifically tailored for a hack/phishing attempt.

This vulnerability is caused due to a problem with the SSH Proxy
infrastructure using only a SOCKS server which for most all Internet
applications causes DNS leaks. The issue of SOCKS servers leaking DNS
requests is well known and documented on the net as a Google search for
"socks dns leaks" will reveal.

The vulnerability has been reported by many users of the Findnot.com
system while sniffing their network connections while using the
service.

These vulnerabilities nullify the specifically claimed features of the
service: "Protects you from DNS spoofing", "When on our system, you are
using our secured DNS system" and "Our encryption guards all your data
from the time it leaves your computer until it reaches our server."

VALIDATION:

Load etherape and sniff on your local internet connection interface.
Connect to the Findnot.com SSH Proxy service, configure IE to use the
Proxies. Load up a few Internet Explorer windows. Visit a few websites
you normally visit. Notice your DNS queries are bypassing your encrypted
SSH Proxy connection and traveling directly to your local ISP or gateway
machine revealing what sites you are accessing to the operator of the
DNS server or anyone inbetween that may also be running etherape or
another sniffer.

SUGGESTED SOLUTION:

1) When Findnot.com SSH Proxy service is used, NEVER use an application
directly pointing to the local SOCKS tunnel.
2) Use SOCKSCAP software that supports 'remote dns lookups'.
3) SOCKSIFY all applications you desire to use with the service with the
SOCKSCAP software.

or

Install Privoxy HTTP proxy, chain it to the Findnot.com SSH Proxy SOCKS
connection, and only use applications that support HTTP Proxy and point
them to the Privoxy software.

or

ONLY use Firefox 1.5.0.2, go to about:config and set
network.proxy.socks_remote_dns to true. This method only protects
Firefox from the problem.

Endnote:        Please note that for readability we have adopted a 'Secunia
Advisories' like format but that this is not a Secunia advisory.

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