Go ICAP Server

ICAPeg Server.

ICAPeg

Open Source multi-vendor ICAP server

Scan files requested via a proxy server using ICAPeg ICAP server, ICAPeg is an ICAP server connecting web proxies with API-based scanning services and more soon. ICAPeg currently supports VirusTotal, Cloudmersive & Clamav for scanning the files following the ICAP protocol. If you don't know about the ICAP protocol, here is a bit about it:

What is ICAP?

ICAP stands for Internet Content Adaptation Protocol. If a content (for example: file) you've requested over the internet to download or whatever, needs adaptation(some kind of modification or analysis), the proxy server sends the content to the ICAP server for adaptation and after performing the required tasks on the content, the ICAP server sends it back to the proxy server so that it may return the adapted content to the destination. This can occur both during request and response.

To know more about the ICAP protocol, check this out.

Table of Contents

• Prerequisites

• Configuration

• Adding a new vendor to ICAPeg

• Developer Guide

• How to Setup Existed Services

  • Echo
  • Virustotal
  • ClamAV
  • Cloudmersive

• Things to keep in mind

• More on ICAPeg

• Contributing

• License

Prerequisites

Before starting to play with ICAPeg, make sure you have the following things in your machine:

1. Golang(latest enough to be able to use go mod)

   You should install at least go version 1.16.

   You can get how to install Golang from here.

2. A proxy server

​ You should configure a Proxy server with ICAPeg, you can get an example from here.

3. Clone the ICAPeg repository

$ git clone https://github.com/egirna/icapeg.git

4. Run the project with the default configuration in config.toml file

5. Run the following command in the directory where you've installed ICAPeg

$ cd ~/ICAPeg

6. Build ICAPeg binary

$ go build .

6. Finally execute the file like you would for any other executable according to your OS, for Unix-based users though

$ ./icapeg

You should see something like, ICAP server is running on localhost:1344 .... This tells you the ICAP server is up and running.

Configuration

​ You can change the default configuration file whatever you want to customize the application.

• Mapping a variable of config.toml file with an environment variable

  This feature is supported for strings, int, bool, time.duration and string slices only (every type used in this project).

  Let's have an example to explain how to map, assume that there is an environment variable in your machine called PORT and you want to assign PORT value to app.port. You should change the value of (port= 1344) to (port= "$_PORT").

  Note: before you use this feature please make sure that the env variable that you want to use is globally in your machine and not just exported in a local session.

  • Config.toml file sections

    • [app] section

      • This section includes the configuration variables that are responsible for the application overall like the port number and current services integrated with ICAPeg.

        [app]
        port = 1344
        services= ["echo", "virustotal", "clamav", "cloudmersive"]
        debugging_headers=true

        • port

          The port number that ICAPeg runs on. The default port number for any ICAP server is 1344, possible values:

          • Any port number that isn't used in your machine.

        • services

          The array that contains integrated services names with ICAPeg, possible values:

          • Integrated services names with ICAPeg (ex: ["echo"]).

        • debugging_headers

          A boolean variable which indicates if debugging headers should be displayed with ICAP headers or not. Debugging headers tell the client shadow service is enabled for example. they start with X-ICAPeg-{{HEADER_NAME}}. possible values:

          • true: Debugging headers should be displayed with ICAP headers.

          • false: Debugging headers should not be displayed with ICAP headers.

          • Any port number that isn't used in your machine.

      • [echo] section

        Note: Variables explained in echo service are mandatory with any service integrated with ICAPeg.

        [echo]
        vendor = "echo"
        service_caption= "echo service"   #Service
        service_tag = "ECHO ICAP"  #ISTAG
        req_mode=true
        resp_mode=true
        shadow_service=false
        preview_enabled = true# options send preview header or not
        preview_bytes = "1024" #byte
        process_extensions = ["pdf", "zip", "com"] 
        # * = everything except the ones in bypass, unknown = system couldn't find out the type of the file
        reject_extensions = ["docx"]
        bypass_extensions = ["*"]
        #max file size value from 1 to 9223372036854775807, and value of zero means unlimited
        max_filesize = 0 #bytes
        return_original_if_max_file_size_exceeded=false

        • Mandatory variables (Variables that should any service has)

          • vendor

            The name of the vendor's service, possible values:

            • The vendor of that service (ex: "echo")

          • service_caption

            Service caption header value.

          • service_tag

            Service caption header value.

          • req_mode

            A boolean variable that indicates whether request mode is enabled or not, possible values:

            • true: Request mode is enabled.
            • false: Request mode is disabled.

            Get more details about request mode from here.

          • resp_mode

            A boolean variable that indicates whether response mode is enabled or not, possible values:

            • true: Response mode is enabled.
            • false: Response mode is disabled.

            Get more details about response mode from here.

          • shadow_service

            A boolean variable that indicates whether shadow service mode is enabled or not, possible values:

            • true: Shadow service mode is enabled.
            • false: Shadow service mode is disabled.

            Note: Shadow service mode is used for debugging purposes. it means that when user/client sent a request to ICAPeg, ICAPeg will send an ICAP response with 204 (No modifications) ICAP status code in case ICAP request has (Allow: 204) header or with 200 (OK) ICAP status code with the original HTTP message in case ICAP request hasn't (Allow: 204) header.

          • preview_enabled

            A boolean variable that indicates whether message preview is enabled or not, possible values:

            • true: Message Preview is enabled.
            • false: Message Preview is disabled.

            Get more details about Message Preview from here.

          • preview_bytes

            It indicates how many bytes of preview are needed for a particular ICAP application on a per-resource basis, possible values:

            • Any string numeric value

          • process_extensions

            It indicates the file types that should be processed and scanned from the service, and possible values:

            • Any string file types.

          • reject_extensions

            It indicates the file types that should be rejected by the service, and possible values:

            • Any string file types.

          • bypass_extensions

            It indicates the file types that should be bypassed by the service and that means the files with these types will not be processed and will not be rejected. They will just be returned to the client as they were sent to ICAPeg from him, and possible values:

            • Any string file types.

            Notes about extensions arrays:

            • Asterisk sign (*****) means every file type except the ones in other arrays. example:

              process_extensions = ["pdf", "zip", "com"] reject_extensions = ["docx"] bypass_extensions = ["*"]

              this example means that any file type will be bypassed except docx type which in reject_extensions, pdf, zip, com types which in process_extensions.

            • Only one array from (process_extensions, reject_extensions, bypass_extensions) arrays should has Asterisk sign (*****).

              process_extensions = ["pdf", "zip", "com"] reject_extensions = ["docx", "pdf", "*"] bypass_extensions = ["*"]

              this configuration is not valid and ICAPeg will not run. another example:

              process_extensions = ["pdf", "zip", "com"] reject_extensions = ["docx"] bypass_extensions = ["*"]

              this configuration is valid and ICAPeg will run normally.

            • Two arrays can't have the same file type. example:

              process_extensions = ["pdf", "zip", "com"] reject_extensions = ["docx", "pdf"] bypass_extensions = ["*"]

              this configuration is not valid and ICAPeg will not run. another example:

              process_extensions = ["pdf", "zip", "com"] reject_extensions = ["docx"] bypass_extensions = ["*"]

              this configuration is valid and ICAPeg will run normally.

        • Optional variables (Variables that depends on the service)

          Notes:

          • You may not use these variables in your service and you may use them, It depends on your service and It's up to you.
          • We will pretend that this service is for file processing and it sends that file to an external API to process it then it gets it back again, So all optional variables depend on that scenario in this service. (It's just a fake scenario service that can do anything not just for processing files).

          • max_filesize

            It's the maximum HTTP message file size that the service can process, possible values:

            • Any valid integer value.

          • return_original_if_max_file_size_exceeded

            A boolean variable that indicates to wether service should return the original file if the file size exceeds the maximum file size or not, possible values:

            • true: Returning the original file.
            • false: Returning 400 Bad request.

            Get more details about request mode from here.

Adding a new vendor to ICAPeg

• How to add a new service for a new vendor.

  After reading the above markdown, read the next section because it may help you while implementing your new service.

Developer Guide

• Developer Guide.

  This is a developer guide which includes a lot of functions to help the developer while implementing his new service.

How to Setup Existed Services

• Echo: It doesn't need setup, it takes the HTTP message and returns it as it is. Echo is just an example service.

• Virustotal.

• ClamAV.

• Cloudmersive.

Testing

• How to test ICAPeg

Things to keep in mind

1. You will have to restart the ICAP server each time you change anything in the config file.

2. You will have to restart squid whenever you restart the ICAP.

3. You need to configure your network(or your browser)'s proxy settings to go through squid.

More on ICAPeg

1. Remote ICAP Servers & Shadowing

2. Logging

3. Monitoring ICAPeg logs with ELK

Contributing

This project is still a WIP. So you can contribute as well. See the contributions guide here.

License

ICAPeg is licensed under the Apache License 2.0.