GoOpenDrop

a Go Implementation and Enhancement of the Awesome Open Source AirDrop implementation work of seemoo-lab openairdrop

Features:

- Support Sending/Receiving Multiple Files. Photos/videos are sent as one request, and any other file of the same Apple UType will be sent together

- Support for BLE 5.0, using BLUEZ with d-bus interface

- Handling all BLE related work, by sending proper Airdrop beacon to intiate Airdrop on Mobiles side, and by capturing BLE beacons to start advertising Zeronconf Service

- Pure Go CPIO Archive implementation written for this project, with auto detection of GZipped CPIO

- Easy Customization and Integration, All Core Requried functionality in one file with a "INTEGRATION POINT" Comment Tag

Required APT Packages:

These the packages required on a Debian based OS

sudo apt install libpcap0.8 libev4 bluez

Required OWL Binaries:

I've included seemoo-lab Compiled OWL Binaries, you can use it, or build it from source: https://github.com/seemoo-lab/owl

Extraction of Apple Keys:

You MUST do the extraction Step of Keys, GoOpenDrop will not generate self signed certificates.

Extraction of the keys benefits:

• this will give the ability to have a verified contact (accept from contact in airdrop settings, and it will show a fixed thumbnail image of type JPEG2000)

• Mobile Configured with Airdrop: Contacts Only Mode, will still accept files from GoOpenDrop

Copy the Extracted keys and validation_record to "Keys" Folder, and run the script: RemovePassphraseKey.sh to remove the passphrase

On Mobile Side, you just add a contact with the same email address used for the extracted Apple ID used for extraction

Follow this repo for extraction:

https://github.com/seemoo-lab/airdrop-keychain-extractor

Example of a verified /Ask post Request:

GoOpenDrop Configuration

At the moment, GoOpenDrop Just use a simple json file for configurations

parameter	Type	Default
inbox_folder	string	INBOX	This is the folder of the Received File from Mobile
outbox_folder	string	OUTBOX	This is the Folder where GoOpenDrop will check for Sending Files to Mobile
owl_wlan_dev_name	string	wlan1	Wlan Interface Name to used for Owl
owl_channel_6_44_149	string	6	wlan Channel to used for Owl
os_downloadedfiles_owner	string		Os Username to change received files owner to
awdl_interface_name	string	awdl0	The Interface name to set Owl to
thumbnail_picture_jp2	string	fixed_thumbnail.jp2	GoOpenDrop will use this file as thumbnail for /Ask requests, file should be of type JP2000, size 540x540
ble_device	string	hci0
airdrop_appleid	string		The Apple ID Account used in Extracting Keys, this used even for broadcasting proper BLE Beacons
airdrop_email	string		Can be Same as Apple ID
airdrop_phone	string		any number will do
airdrop_server_hostname	string	GoOpenDrop	The device Name that will appear which mobile phone discover GoOpenDrop
airdrop_server_model	string	MacbookPro5.1	No need to modify this
airdrop_server_port	int	8772	No need to modify this
apple_root_cert	string	certs/apple_root_ca.pem	Apple Root Certificate, already included in this repo
extracted_certififcate	string	keys/certificate.pem	Extracted Certificate
extracted_certkey	string	keys/key_noenc.pem	Extracted Certificate Key, after removing the encryption
extracted_validation_recoed	string	keys/validation_record.cms	Extracted Validation Record

Sending/Receving Files:

To Send Files, Create a folder in "OUTBOX" with the device name of the receiver, just drop any files there, they will be sent once the device is discovered.

Receiving, GoOpenDrop will accept any file and will create a folder in INBOX with the device name of the sender. You can customize this functionality by modifying the file:

main.go

func checkSender(name string) bool {
	// INTEGRATION POINT
	// ADD INTEGRATION HERE IF NEEDED, You can call your own API server to decide accept or reject /Ask request 
	return true 

}

Build

To build simply run the scripts:

./Build_Linux64.sh

Or

./Build_Pi.sh

The build scripts will copy all required files along with the binary to out folder

Running

At the moment, since GoOpenDrop restart BLE interface, wlan interface, it requires to run as Root.

run GoOpenDrop compiled

sudo ./goopendrop ./config.json

Issues/Limitations and security

• GoOpenDrop Require Running as Root, will try to fix this as soon as I find the correct capabilities to give the binary, or find a better solution to restart BLE and wlan interfaces
• Client Verification, GoOpenDrop Does not verify the client sending the files, this can easily be fixed by writing a custom TLS verification function, which will extract client details and verify it with received apple signature in received validation record
• since GoOpenDrop currently requires running as root, a client can use malicious device name, or malicious cpio archive and escape path or overwrite system files

Tested Wifi Module :

• Alfa AWUS036ACM
• Linksys AE6000

Tested Hardware/os:

• Any PC running Ubuntu 22.04 with bluetooth module and one of the listed wifi modules
• Raspberry Pi 400/Raspberry Pi OS Lite

Compatible Wifi Modules

For compatible Wifi Modules with Active Monitoring, check this awesome shortlist:

https://github.com/morrownr/USB-WiFi/blob/main/home/The_Short_List.md

I've only tested the ones listed above, other on the list should work as long as they have Active Monitoring

I have not tested patched Wifi Module or running Owl with -n for nexamon patched interfaces