Squid Web Proxy 2.3 Reverse Proxy Vulnerability

                                                source: http://www.securityfocus.com/bid/3062/info

Squid is a free client-side web proxy that retrieves cached web pages for quick browsers and a reduction in bandwidth consumption.

Squid servers, when configured as an "HTTP accelerator only", may allow remote attackers to use them as port scanners. There is also a potential that they will grant proxied access to the malicious user.

It should be noted that this is not a default configuration for affected versions of Squid Web Proxy.

1. Set squid to HTTPD_accel mode, with a particular host and strict
acl's

2. export httpd_proxy="HTTP://squid-server:port"


3. lynx HTTP://victim:port/

Actual Results: You get a HTTP 200 code if the port is open and
sometimes a response with some services SSH, SMTP, etc

Expected Results: Should be access denied (403)