# Exploit Title: sudo -e - a.k.a. sudoedit -unauthorized privilege escalation# Date: 07-23-2015# Exploit Author: Daniel Svartman# Version: Sudo <=1.8.14# Tested on: RHEL 5/6/7 and Ubuntu (all versions)# CVE: CVE-2015-5602.
Hello,
I found a security bug insudo(checked in the latest versions of sudo
running on RHEL and ubuntu) when a user is granted with root access to
modify a particular file that could be located in a subset of directories.
It seems that sudoedit does not check the full path if a wildcard is used
twice (e.g. /home/*/*/file.txt), allowing a malicious user to replace the
file.txt real file with a symbolic link to a different location (e.g.
/etc/shadow).
I was able to perform such redirect and retrieve the data from the
/etc/shadow file.
In order for you to replicate this, you should configure the following line
in your /etc/sudoers file:
<user_to_grant_priv>ALL=(root) NOPASSWD: sudoedit /home/*/*/test.txt
Then, logged as that user, create a subdirectory within its home folder
(e.g. /home/<user_to_grant_priv>/newdir) and later create a symbolic link
inside the new folder named test.txt pointing to /etc/shadow.
When you run sudoedit /home/<user_to_grant_priv>/newdir/test.txt you will
be allowed to access the /etc/shadow even if have not been granted with
such access in the sudoers file.
I checked this against fixed directories and files (not using a wildcard)
and it does work with symbolic links created under the /home folder.
