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The Backdoor Factory Proxy (BDFProxy) v0.3.8

For security professionals and researchers only.

Join the chat at Black Hat Arsenal

###NOW ONLY WORKS WITH v.0.17 >= MITMPROXY >= v.0.11


 # sudo echo 1 > /proc/sys/net/ipv4/ip_forward  # linux
 # sudo sysctl -w net.inet.ip.forwarding=1 # macOS
 docker pull secretsquirrel/bdfproxy
 docker run -it -p 8080:8080 secretsquirrel/bdfproxy bash
 # ./

To install on Kali:

apt-get update
apt-get install bdfproxy

Black Hat USA 2015:



DerbyCon 2014:


About 18 minutes in is the BDFProxy portion.

Contact the developer on:

IRC: #BDFactory 


This script rides on two libraries for usage: The Backdoor Factory (BDF) and the mitmProxy.

###Concept: Patch binaries during download ala MITM.

###Why: Because a lot of security tool websites still serve binaries via non-SSL/TLS means.

Here's a short list:
	Microsoft - MS Security Essentials
	Almost all anti-virus companies

Yes, some of those apps are protected by self checking mechanisms. I've been working on a way to automatically bypass NSIS checks as a proof of concept. However, that does not stop the initial issue of bit flipping during download and the execution of a malicious payload. Also, BDF by default will patch out the windows PE certificate table pointer during download thereby removing the signature from the binary.


Pefile - most recent
mitmProxy - Kali Build .10
BDF - most current
Capstone (part of BDF)

##Supported Environment: Tested on all Kali Linux builds, whether a physical beefy laptop, a Raspberry Pi, or a VM, each can run BDFProxy.

##Install: BDF is in bdf/

Run the following to pull down the most recent:



git clone bdf/

If you get a certificate error, run the following:


And exit [Ctr+C] after mitmProxy loads.

##Usage: Update everything before each use:




You will need to configure your C2 host and port settings before running BDFProxy. DO NOT overlap C2 PORT settings between different payloads. You'll be sending linux shells to windows machines and things will be segfaulting all over the place. After running, there will be a metasploit resource script created to help with setting up your C2 communications. Check it carefully. By the way, everything outside the [Overall] section updates on the fly, so you don't have to kill your proxy to change settings to work with your environment.

But wait! You will need to configure your mitm machine for mitm-ing! If you are using a wifiPineapple I modded a script put out by hack5 to help you with configuration. Run ./ and enter in the correct configs for your environment. This script configures iptables to push only http (non-ssl) traffic through the proxy. All other traffic is fowarded normally.



Here's some sweet ascii art for possible phyiscal settings of the proxy:

Lan usage:


Wifi usage:



Suppose you want to use your browser with Firefox and FoxyProxy to connect to test your setup.

	Update your config as follows:
	transparentProxy = None

	Configure FoxyProxy to use BDFProxy as a proxy.
	Default port in the config is 8080.

##Logging: We have it. The proxy window will quickly fill with massive amounts of cat links depending on the client you are testing. Use tail -f proxy.log to see what is getting patched and blocked by your blacklist settings. However, keep an eye on the main proxy window if you have chosen to patch binaries manually, things move fast and behind the scences there is multi-threading of traffic, but the intial requests and responses are locking for your viewing pleasure.

##Attack Scenarios (all with permission of targets): -Evil Wifi AP -Arp Redirection -Physical plant in a wiring closet -Logical plant at your favorite ISP

##Bug Reporting

Bugs happen, but if I can't understand your issue, I can't help you.

Submit issues here:

Include the following information from the output of the these commands (use pastebin for the longer commands):

# bdfproxy only supports v11 -> v17
$ mitmproxy --version

$ uname -a

# Use pastebin perhaps
$ cat bdfproxy.cfg 
$ ./

###Change Log:


Support for BDF Preprocessor and mitmProxy v17


Added configuration options in bdfproxy.cfg to support PE code signing from BDF => CODE_SIGN See BDF README for details


Remove python-magic dependencies because there are two libraries that are named as such. Which is confusing.


Add support for BDF Import Directory Patching into the a code cave vs a new section. Update IDA_IN_CAVE to True in the bdfproxy.cfg file for this. EXPERIMENTAL...


Added support for the PE replace method, replace downloaded binary with an attacker supplied one. To use change PATCH_METHOD to replace and provide a SUPPLIED_BINARY


Added support for onionduke. To use change PATCH_METHOD to onionduke and SUPPLIED_BINARY to the binary that you wish to bind to the target executable.

Added support to set the check and patching of the requestedExecutionLevel in the PE manifest as highestAvailable for both x86 and x86_64 PE binaries. Set RUNAS_ADMIN as True.

Added support to set whether to support legacy XP machines via the XP_MODE flag as True. This can have evasion against AVs as their emulators may fail if this setting is set to FALSE.


Patch Binaries via MITM: BackdoorFactory + mitmProxy.






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