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# Exploit Title: Budabot !calc Denial of Service
# Date: 15-10-2018
# Exploit Author: Ryan Delaney
# Author Contact: ryan.delaney@owasp.org
# Author LinkedIn: https://www.linkedin.com/in/infosecrd/
# Vendor Homepage: http://budabot.com/
# Software Link: https://github.com/Budabot/Budabot/releases
# Version: 0.6 -> 4.0
# Tested on: 4.0
# CVE: CVE-2018-19290

1. Description

In modules/HELPBOT_MODULE in Budabot 0.6 through 4.0, lax syntax validation
allows remote attackers to perform a command injection attack against the
PHP daemon with a crafted command, resulting in a denial of service or
possibly unspecified other impact. In versions before 3.0,
modules/HELPBOT_MODULE/calc.php has the vulnerable code; in 3.0 and above,
modules/HELPBOT_MODULE/HelpbotController.class.php has the vulnerable code.

2. Proof of Concept

Start the Budabot listener, set valid configuration options, and wait for
the chatbot to announce it's ready in-game.
Send the chatbot a private message containing "!calc 5 x 5", and the
Budabot listener will terminate.

3. Solution

Edit the relevant file to remove "x" and " " (space) from the strspn() mask.
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