An attacker with local access the to medical office computer can
escalate his Windows user privileges to "NT AUTHORITY\SYSTEM" by
exploiting a race condition in the Elefant Update Service during the
repair or update process. When using the repair function, the service queries the server for a
list of files and their hashes. In addition, instructions to execute
binaries to finalize the repair process are included. The executables are executed as "NT AUTHORITY\SYSTEM" after they are
copied over to the user writable installation folder (C:\Elefant1). This
means that a user can overwrite either "PostESUUpdate.exe" or
"Update_OpenJava.exe" in the time frame after the copy and before the
execution of the final repair step. The overwritten executable is then executed as "NT AUTHORITY\SYSTEM".
The vendor fixed the issue in version 1.4.2.1811 (or higher) of the Elefant Software Updater which can be downloaded from hasomed.de/produkte/elefant/ https://hasomed.de/produkte/elefant/ or via the Elefant Software Updater itself.
Configurations
Workarounds
While workarounds such as modifying the Elefant windows firewall
rules and manually adjusting file permissions in the installation folder
are feasible workarounds for some of the vulnerabilities, it is
recommended to install the patches provided by the vendor.
Exploits
Credits
finder
Tobias Niemann, SEC Consult Vulnerability Lab
finder
Daniel Hirschberger, SEC Consult Vulnerability Lab