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Zeek HTTP2 Analyzer Plugin

This plugin provides an HTTP2 (RFC 7540) decoder/analyzer for Zeek 4.0+. If you need this capability for older instances of Zeek (Bro), i.e., 3.x, 2.6.x or older, please refer to previous versions of the plugin.

The events exposed attempt to mimic the events exposed by the native HTTP analyzer


Installation

Requirements

Nghttp2

Nghttp2 1.11.0 or greater is required. The plugin uses the decompression libraries and some portions of the API used are not supported prior to that version.

nghttp2 Library - https://github.com/nghttp2/nghttp2

On CentOS 7:

# sudo yum install libnghttp2-devel

On Ubuntu 20.04:

# apt install libnghttp2-dev

Alternatively install the library manually from the repo.

Brotli

Brotli is required as it is used quite often by popular websites and the analyzer automatically attempts to decompress data frames.

On CentOS 7:

# sudo yum install libbrotli-devel

On Ubuntu 20.04:

# apt install libbrotli-dev

Alternatively install the library manually. It can be found at https://github.com/google/brotli. The latest release can be found at https://github.com/google/brotli/releases/latest. After downloading the latest release, follow these steps to compile and install the library:

tar -zxvf <release file>
cd brotli-<version>
mkdir build && cd build
../configure-cmake
make
make test
make install

Zeek Package Manager

Using the Zeek Package Manager is the recommended way to install this plugin. The Zeek Package Manager (zkg) is included with installations of Zeek 4.0 and newer.

Before attempting to install the plugin, ensure Zeek's binary path is available in your PATH environment variable. For example if you installed Zeek via binary package, you would need to do:

# export PATH=$PATH:/opt/zeek/bin

After setting the PATH properly, you can install the plugin using one of the following methods:

  • From the repo clone directory:

    # zkg install .
    
  • Using the github repo directly:

    # zkg install https://github.com/MITRECND/bro-http2
    
  • Using the official source:

    # zkg install zeek/mitrecnd/bro-http2
    

NOTE If you had an older version of zkg or the original bro package manager installed, the path might show up as bro/mitrecnd/bro-http2. Please use that path or update your zkg configuration located, by default, in ~/.zkg/config.

Installing Older Versions

If you are still running an older version of Zeek (Zeek 3.x, Bro 2.6.x or older), you can install a previous version of the plugin using zkg, utilizing the --version argument to specify a specific source tag or branch. The following will install a version compatible with Bro 2.6.x.

  # zkg install zeek/mitrecnd/bro-http2 --version 0.4.2

NOTE While using an older version ensures compatibility with an older version of Zeek/Bro, there have been some changes and bug fixes made to the code, so performance may not be optimal and issues may arise.

Usage

You should see the following output from zeek if successfully installed:

> zeek -NN mitrecnd::HTTP2
mitrecnd::HTTP2 - Hypertext Transfer Protocol Version 2 analyzer (dynamic, version 0.6.0)
    [Analyzer] HTTP2 (ANALYZER_HTTP2, enabled)
    [Event] http2_request
    [Event] http2_reply
    [Event] http2_stream_start
    [Event] http2_stream_end
    [Event] http2_header
    [Event] http2_all_headers
    [Event] http2_begin_entity
    [Event] http2_end_entity
    [Event] http2_entity_data
    [Event] http2_content_type
    [Event] http2_event
    [Event] http2_data_event
    [Event] http2_header_event
    [Event] http2_priority_event
    [Event] http2_rststream_event
    [Event] http2_settings_event
    [Event] http2_pushpromise_event
    [Event] http2_ping_event
    [Event] http2_goaway_event
    [Event] http2_windowupdate_event
    [Event] http2_continuation_event
    [Type] http2_settings_unrecognized_table
    [Type] http2_settings
    [Type] http2_stream_stat

To use/load the http2 analyzer, add the following to your config (e.g., local.zeek):

@load http2

The analyzer will create a new log file called "http2.log"

To use/load the http2 intel framework extensions add the following to your config:

@load http2/intel