Challenge:
Name: Kill Chatbot
Description: Permanently disable the support chatbot so that it can no longer answer customer queries.
Difficulty: 5 star
Category: Vulnerable Components
Expanded Description: https://pwning.owasp-juice.shop/part2/vulnerable-components.html
Tools used:
None.
Resources used:
Solution Guide https://pwning.owasp-juice.shop/appendix/solutions.html
Methodology:
The expanded description for this challenge heavily suggests that the vulnerability to exploit has something to do with the code which runs the bot. First thing’s first, I found the package which runs the bot in the application-configuration file, “juicy-chat-bot”.
Here I found that there’s a GitHub repository for the package, so I went there and downloaded the package.
Next, I checked out what the dependencies were, thinking there may be a library here which has a known vulnerability to exploit.
Unfortunately there was no such luck. I then spent significant time poring over each file in the GitHub repository, trying to find a way to kill the bot. My lack of JavaScript experience, however, was a serious hindrance to this effort. Having written very, very little JS over the course of my education, I struggled to figure out what the intended solution for this challenge was. I saw the following piece of code and knew it had to have something to do with the solution, but had zero clue how to exploit it.
![var
users =
idmap:
(token, name) {
addUser :
function
. idmap[token] = name
this
(token) {
function
get :
. idmap[ token]
return this
train ( ) {
function
trainingset .data {
query.utterances .map((utterance) {
model.addDocument(trainingSet.lang, utterance, query .intent)
query .answers {
model.addAnswer(trainingSet.lang, query.intent, answer)
{ training.state =
return
true
process (query, token) {
function
(users .get(token)) {
if
model .process(trainingset . lang, query)
return
{ action:
' unrecognized' ,
body: 'user does not exist'
return](https://curiositykillscolby.files.wordpress.com/2021/01/image-2.jpeg?w=573)
So I went to the Solution Guide and found this string: admin”); process=null; users.addUser(“1337”, “test
This string inserts JS code into the “username” field which kills the bot, something I’m still trying to wrap my head around.
Prevention and Mitigation Strategies:
OWASP Vulnerable Dependency Management Cheat Sheet
Lessons Learned and Things Worth Mentioning:
JavaScript (and possibly other languages, I haven’t checked yet) allows user inputs to be interpreted as code if the inputs aren’t sanitized properly. This is something entirely new to me, and as I’ve never seen it before I wouldn’t have been able to work it out without the Solution Guide.
Curiosity Kills Colby 
![https://curiositykillscolby.files.wordpress.com/2021/01/image-2-1.jpeg?w=806"](https://curiositykillscolby.files.wordpress.com/2021/01/image-2-1.jpeg?w=806"){kind=link}