ac_patcher

AnyConnect Patcher for Freedom

Backstory

I got tired of AnyConnect always stealing/locking my route tables, especially after I started to use more containerization. It just got really frustrating to need to continually disconnect/reconnect, and/or hit up the systems admin person (me) to change the VPN side of things.

How it works

The AnyConnect Linux Binary uses the following C++ method: CHostConfigMgr::StartInterfaceAndRouteMonitoring() The following Python script finds that method, then backtracks to where that method is being called from, and then NOPs out that call. Since this address will change in each version of AnyConnect, I needed something that would do this process automatically, hence the scripting of radare2.

Requirements

• AnyConnect must installed

How to use it.

Use at workstation

Install dependancies: Note: radare2 is no longer included with Ubuntu after 20.04. You can download binaries from: https://github.com/radareorg/radare2/releases

dpkg -i radare2_5.3.1_amd64.deb

Note: As of 20210722 - r2pipe is not compatible with radare2 5.4.0 - the instructions on this page were tested with various versions up to 5.3.1

pip3 install r2pipe

Run the patcher.

This will stop the system service, dissassemble the binary looking for the methods, and patch it out and then restart the service. You'll need to sudo this for elevated privileges, due to the following:

1. the default installation directory /opt/cisco/anyconnect/ requires elevated privileges for writing
2. stopping/starting the vpnagentd service requires service management privs.

sudo ./anyconnect_patcher.py

Use in container

On host must be installed Docker with support docker-compose

docker compose version
Docker Compose version v2.17.2

• All dependencies will be install inside container
• ac_patcher will be perform inside container which will be have permissions stop/start vpnagentd to host

Install and Run

docker compose build
docker compose up
...
Here will be logs of ac_patcher
...
docker compose down

or

docker compose up --build
...
Here will be logs of ac_patcher
...
docker compose down

Version Compatibility:

Tested / Confirmed with:

• 4.9.00086
• 4.9.01095
• 4.9.02028 (Unable to test, Mac only)_
• 4.9.0304x
• 4.9.04053
• 4.9.05042
• 4.9.06037
• 4.10.00093
• 4.10.01075
• 4.10.04071