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Proxy Hack Client: The Ultimate Guide to Web Proxy Auto-Discovery and Squid Configuration



Nevertheless, a WPAD protocol is used to enable clients to auto discover the proxy settings, so manual configuration is not needed. All that needs to be done on the clients themselves is enabling the auto-detection of proxy settings.




Proxy Hack Client



The first thing we need to do is create the wpad.dat file, which contains a JavaScript code that tells the web browser the proxy hostname and port. Each web browser that supports WPAD provides the following functions in a secure sandbox environment. All the other functions are prohibited.


After that, we can execute the following command on the wpad.infosec.local server to verify whether Firefox is actually able to access the wpad.dat file. In the output, we can see that the client from IP address 192.168.1.13 is accessing the wpad.dat file, which is our Firefox browser.


When browsing with the browser after all the configured settings, we can see the logs of the proxy server to check whether the proxy is actually serving the web sites. We can visit www.wikipedia.com and execute the tail command in the Pfsense firewall; the following will be displayed, which verifies that www.wikipedia.com is actually being queried by the proxy server.


In order to attack the clients on the network, we first have to rely on auto-configuration being enabled in their browsers, which by default is not. Nevertheless, this option is often enabled in enterprise environments, which makes it a possible attack vector.


WPAD auto-discovery is often enabled in enterprise environments, which enables us to attack the DNS auto-discovery process. We can do that by setting up a proxy on our attacking machine and instruct all the clients to forward the requests through our proxy, which enables us to save all the requests in a .pcap file. We could also change the responses which are being returned to the user to present different content.


Dejan Lukan is a security researcher for InfoSec Institute and penetration tester from Slovenia. He is very interested in finding new bugs in real world software products with source code analysis, fuzzing and reverse engineering. He also has a great passion for developing his own simple scripts for security related problems and learning about new hacking techniques. He knows a great deal about programming languages, as he can write in couple of dozen of them. His passion is also Antivirus bypassing techniques, malware research and operating systems, mainly Linux, Windows and BSD. He also has his own blog available here:


In the worst case, an attacker may use proxy hacking to introduce malware or other viruses to the victim's computer. In a less malicious but still devious example, the attacker may try to gain an advantage over a competitor or get advertising revenue by redirecting traffic to their fraudulent website. The latter is also known as SEO hijacking, Content scraping, page hijacking or pagejacking, and is distinct from watering hole attacks, attack proxies, web proxies or attacks via proxy.


In a proxy hack, the attacker duplicates a highly ranked search result webpage, and tries to get their copy to rank higher in a search than the original. The goal of the attacker is to get victims to go to the imitation website instead of the original. This may be with the simple goal of getting advertisement revenue or paid referral links from stolen content. Alternatively, the attacker may try to use the page to introduce malware or other viruses to the victim's computer. There are two main ways that the attacker duplicates the content -- by using a malicious web proxy or by outright duplicating the target content.


In the original form of a proxy hack, the attacker creates a malicious web proxy that points to the target victim page. The attacker then creates links to their proxied URL that claims to be the original content. When the search engine indexer checks the links to the proxy, it is seen as having the same content as the victim page. This method of proxy hacking has been mostly mitigated by changes to Google's ranking algorithm.


In another form of proxy attack, the attacker creates a duplicate of the targeted webpage on another web server. The entire content of the site is copied instead of just linked or proxied. Large proxy hacking operations may use content scraping to automatically steal and reproduce webpages.


Regardless of the method of duplicating the content, the attacker then attempts to make their copy rank higher in Google search or other search engines than the original website. Proxy hacking pages use a variety of methods to rank higher than the original webpage.


There is no way to fully protect a site against proxy hacking and duplicated content, as it is done on sites the original site owners do not control and third-party search engines. But, by following SEO best practices, a company can defend against and reduce the efficacy of proxy hacking.


Organizations should protect their domain against automated content scraping. This can mean blocking malicious bots and spiders from accessing their site. They need to block malicious web proxies and use scrape shields to obfuscate content. Many web servers and content delivery networks (CDNs) now offer malicious bot fighting and filtering tools that can help to stop proxy hacking.


When a site owner suspects that their website is the victim of a proxy hack, they should search for a phrase that should be unique, or almost unique, to their own content. Their page should be prominent in search results. If, however, a duplicate of that content shows up, it may be a proxy page.


Proxy page URLs typically look different from genuine pages. They often contain the full link to another domain. For example, a malicious link may appear similar to www.examplebadsite.com/nph-proxy/http/www.techtarget.com/definition. Notice how the middle of the link contains http and www which normally only appear at the start of the link and .com which should be at the end of the domain name.


Watering hole attacks are similar because they also seek to take advantage of sites that the victim user is trying to go to. In watering hole attacks, the attacker hacks the original website server and changes it to serve malicious content instead of copying the content.


Attack proxy is a tool used by hackers to automatically scan and attack a website. They can apply common attacks and check for vulnerabilities of a site or server. Popular attack proxies are OWASP Zed Attack Proxy and Burp Suite by PortSwigger.


Hacking via proxy, or using a proxy, is when an attacker uses another computer rather than their own to perform the attack. This may be a dedicated attack computer or another victim's computer that the attacker uses as a jumping-off point to perform another attack.


There isn't currently proxy support. I tried using superagent-proxy, but adding that dependency added 1.2 MB to the package, so I left it out until I could find a better solution. What was the hack you implemented previously?


Previous hack was actually a change that someone had made to the code but then had somehow got overwritten and then never got pushed back in (can't access the github page anymore though) which I borrowed the changes from ... basically ...


Even if you don't change the SDK, are you able to give some guidance on where to make the changes in the new version? Still on a learning curve with javascript and unfortunately stuck behind a corporate proxy.


I don't have the code where I was trying the proxy anymore, but I believe you can set the proxy in the callApi function here. If you're generating the SDK yourself, you would make the change to the ApiClient template.


Just an update on this ... one of my colleagues ( tuttinator ) has managed to get the new javascript platform client working through a proxy by making some changes, so listing here in case anymore else is in need.


Chisel is a fast TCP tunnel, transported over HTTP, secured via SSH. Single executable including both client and server. Written in Go (golang). Chisel is mainly useful for passing through firewalls, though it can also be used to provide a secure endpoint into your network. Chisel is very similar to crowbar though achieves much higher performance.


Of the four items, only the remote port is required. If no local-host is given, it will assume 0.0.0.0 on the client. If no local-port is give, it will default to the same as the remote-port. If no remote-host is given, it will default to the server. You can give it R for local-host to indicate that you want to listen on the remote host (ie, open the listener on the server). In that case, the tunnel will go in the reverse direction.


One thing I encountered during a test was that after putting these match and replace rules in, the client was extraordinarily persistent in retrying WebSockets connections and caused a lot of unwanted traffic in my HTTP history. If you are dealing with the socket.io library, it is probably easiest to use Method 1 above. If you have a different library or situation you may have to add more rules to convince the client that the server does not support WebSockets or even cripple the WebSockets functionality in the client library.


In previous blog post we discussed how we use the TPROXY iptables module to power Cloudflare Spectrum. With TPROXY we solved a major technical issue on the server side, and we thought we might find another use for it on the client side of our product.


When building an application level proxy, the first consideration is always about retaining real client source IP addresses. Some protocols make it easy, e.g. HTTP has a defined X-Forwarded-For header[1], but there isn't a similar thing for generic TCP tunnels.


For certain applications it may be okay to ignore the real client IP address. For example, sometimes the client needs to identify itself with a username and password anyway, so the source IP doesn't really matter. In general, it's not a good practice because...


A second method was developed by Akamai: the client IP is saved inside a custom option in the TCP header in the SYN packet. Early implementations of this method weren't conforming to any standards, e.g. using option field 28, but recently RFC7974 was ratified for this option. We don't support this method for a number of reasons: 2ff7e9595c


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