Link to the repo at the bottom...
Precursor to this post: https://ratil.life/slackbots-for-fun-and-profit/

A few months back I decided to find a way to lighten the load of ad hoc vulnerability scanning requests by our system owners.  One of our biggest time sucks was "Can you scan this"..."Ok I fixed it, scan again."

Given the prevelance of Slack and associated bots, I thought it would be a good idea to try to write my own for scanning. Enter the InsightVM Slack Bot!

Ruby Version

Initially I wrote the entire bot in Ruby using the Ruby Slack Client and the Nexpose API Ruby Gem.  At the time, the Nexpose Gem was the preferred (and only supported) way to interact with the Nexpose API which was the primary mechanism for initiating scans. This approach worked...mostly, but there were a few problems:

  • The Slack Ruby Client seemed a bit unstable for some reason. The bot would run for days at a time and then just randomly lose connection to Slack. At other times, the bot would only last a few hours before the connection was lost. This could 100% been an issue with my code but I was never able to determine the culprit.
  • In order to rate limit the scans I needed a queuing system and ended up using the Ruby Resque Gem. This worked really well for my purposes and even provided a pretty cool web interface for tracking jobs. The downside was the this also required me to run a Redis database to house the queue information. This was just an additional dependency.
  • Due to (probably my lack of coding expertise) the structure of the queue mechanism and the tasks I was trying to accomplish, the program structure was pretty ugly. I had a base script that ended up calling 3 other Ruby scripts that operated two different queues for scan initiation and scan status tracking. I could only figure out how to run the script directly (not as a service or anything else). This made debugging difficult and was definitely not the most user friendly thing in the world.

Python Version

Then Rapid7 released version 3 of the InsightVM API (after they rebranded Nexpose as InsightVM) as a RESTful API. This update freed me from the Ruby requirement and after a few months of debating, I finally decided to port the bot over to Python (3 of course). This decision was also largely due to the work my team did on developing an InsightVM Helpers class to assist in interacting with the API.

The Python version of the bot differs from the Ruby version in a few key ways:

  • Instead of Resque and Redis as my queuing and rate limiting mechanism, I was able to make use of the native Python threading capabilities. This reduced my dependencies and also was much cleaner to implement in code.
  • Using the new InsightVM API, I was more cleanly able to execute the scan functions that I needed AND the new API is much faster in most cases. There are a few wonky spots but I was able to overcome those with some interesting code features.
  • The Python Slack Client seems much more stable and I have not had any random crashes or disconnects using this client.
  • I forced myself to write tests for this project which was a rewarding experience itself.

The major drawback of using the new V3 API is figuring out which site(s) an asset is part of. In the Ruby Gem, there was an ad hoc scan function that would simply scan the asset as part of whatever site the asset had been scanned with last without the need to specify a site parameter.  Therefore I did not have to figure that part out.  In V3, I have to poll every site to determine which one(s) an asset is part of.  Using the joblib library and the associated Parallel and delayed classes, I was able to get this part done really quickly by making a bunch of parallel calls to determine site membership. The end effect on the speed of starting a scan is negligible (if not faster) compared to how I was able to ignore this part in Ruby.

Usage

The setup of the bot is covered on on GitHub page below so I will not cover that here.  The bot is simple enough to use once installed and running. A user simply has to add the bot to a channel or do a direct message with the bot and scan an asset like so: @insightvm_bot scan 192.168.1.1.  

The bot then immediately responds to indicate receipt of the request and then starts working on figuring out how exactly to scan the asset.  The bot accepts both IPs and hostnames so the first task is to sort that out by regexing out IPs and hostnames.  Then those IPs and hostnames are checked against every site in InsightVM to determine what sites they are a part of (unfortunately the API does not return site membership with the asset search function so this is a necessary inefficiency). If an IP or hostname is not part of a site, a forward/reverse lookup is conducted to ensure the asset is not listed as the opposite.  Assuming the asset(s) are part of one site, a scan is triggered and a message posted to Slack.  If there are any errors, they are returned to the user in Slack as a message.

If an asset is part of multiple sites, the site listing is returns and the bot asks the user to pick a site to scan the asset in the context of using: @insightvm_bot scan 192.168.1.1 site 123

The bot then continues to check each minute for scan completion. Once the scan is complete, the bot posts summary results to Slack. Errors in the scan will return the error message as a message in Slack.

Way Forward

I want to add additional features such as full site scans (already have a branch for that), report generation, and perhaps other maintenance tasks. One of the biggest challenges I have right now is authenticating users.  The bot runs as a low-privilege InsightVM user which restricts some of the things it can do including retrieving user access details.  

I have been reluctant to make the bot InsightVM user a Global Admin due to security concerns.  That being said, if I did this, then the bot could take a user's email from Slack and ensure that the user has access to the sites/assets they are trying to scan.  This would also be helpful for maintenance actions as only other Global Admins would be allowed to perform those actions.

Summary

This is my first project beyond just simple scripting and my first open-source project. I learned a ton in creating this bot and making the bot has certainly increased my confidence as a Python programmer.  I relied heavily on my teammates for knowledge and insight about how best to accomplish different parts of the bot. I also have to thank Rackspace for letting me open-source this so that others may benefit.

Well, here's the link.  It's open-source now.

https://github.com/rackerlabs/insightvm_slackbot