KERUI K259 5MP Wi-Fi (Tuya Smart Security Camera) contains a code execution vulnerability
KERUI K259 5MP Wi-Fi / Tuya Smart Security Camera firmware v33.53.87 contains a code execution vulnerability in its boot/update logic: during startup /usr/sbin/anyka_service.sh scans mounted TF/SD cards and, if /mnt/update.nor.sh is present, copies it to /tmp/net.sh and executes it as root, allowing an attacker with physical access to run arbitrary commands.
Vulnerable Endpoint : /usr/sbin/anyka_service.sh, /usr/bin/update_entry
Trigger File : update.nor.sh (placed at the root of the mounted tf/sd card)
/usr/sbin/anyka_service.sh
...
start_update()
{
/usr/bin/update_entry &
}
...
umount /mnt
mount_tf_card
sh /usr/sbin/tf_update.sh
start_update
i=5
while [ $i -gt 0 ]
do
sleep 1
pid=`pgrep /usr/bin/update_entry`
if [ -z "$pid" ]; then
echo "The /usr/bin/update_entry has exited, start_update!!!"
break
fi
i=`expr $i - 1`
done
if [ $mount_status -eq 1 ]; then
if [ -f /tmp/enter_update ]; then
echo "/tmp/enter_update file is exist, should be update!"
update_flag=1
else
echo "/tmp/enter_update file is not exist!"
update_flag=0
fi
else
update_flag=0
fi
if [ $update_flag -eq 1 ]; then
/tmp/net.sh
fi
...
/usr/bin/update_entry (pseudo / decompiled)
int sub_108f8()
{
FILE *v0; // r6
char v2[152]; // [sp+0h] [bp-98h] BYREF
memset(v2, 0, 0x80u);
v0 = popen("find /mnt/ -maxdepth 1 -name \"update.nor.sh\"", "r");
if (v0)
{
while (fgets(v2, 128, v0))
{
if (strstr(v2, "update.nor.sh"))
{
puts("==================find update.nor.sh!! start update.nor.sh==================");
system("cp -f /mnt/update.nor.sh /tmp/net.sh");
usleep(0x2710u);
system("chmod 777 /tmp/net.sh");
system("touch /tmp/enter_update");
system("sync");
usleep(0x2710u);
break;
}
}
pclose(v0);
return 0;
}
else
{
puts("error:popen failed");
return -1;
}
}
create /update.nor.sh at the root of an sd/tf card with content
insert the sd card and reboot the device.
on successful exploitation the device will copy /mnt/update.nor.sh to /tmp/net.sh, mark it executable and run it. a telnet service (or any arbitrary command) will be started and allow root shell access.
