IBM Informix File Clobbering during Install
10/1/2006
Overview
From the Website
“IBM Informix® Dynamic Server (IDS) is a strategic data server in the IBM Information Management Software portfolio that provides blazing online transaction processing (OLTP) performance, legendary reliability, and nearly hands-free administration to businesses of all sizes. IDS 10 offers significant improvements in performance, availability, security, and manageability over previous versions, including patent-pending technology that virtually eliminates downtime and automates many of the tasks associated with deploying mission-critical enterprise systems.†Vulnerability
During installation the installserver script creates a file in /tmp called installserver.txt an unprivileged user can symlink this file to another file causing the target file have the contents of installserver.txt appened to it.
<code>
vapid:/tmp# ls -l /tmp/installserver.txt
lrwxrwxrwx 1 lwc lwc 11 Oct 1 18:27 /tmp/installserver.txt -> /etc/passwd
After installation the contents of installserver.txt was appened to /etc/passwd. File Permissions
The default file permissions of the installation package are too open, an unprivileged user can take advantage of an installation by a privileged user by injecting code into the installer script.
nobody@vapid:/home/auditor/test$ ls -l
total 273168
-rw-rw-rw- 1 root root 10328050 Aug 1 2005 Gls.rpm
-rw-rw-rw- 1 32100 1360 5125418 Aug 1 2005 IIF.jar
-rw-rw-rw- 1 root root 84374286 Aug 1 2005 IIFServer.rpm
-rw-rw-rw- 1 root root 786557 Aug 1 2005 Message.rpm
drwxrwxrwx 2 32100 1360 4096 Aug 1 2005 doc
-rw-r--r-- 1 auditor auditor 140032000 Oct 1 18:21 iif.10.00.UC3R1TL.Linux.tar
-rwxr-xr-x 1 32100 1360 4424 Aug 1 2005 install_rpm
-rwxrwxrwx 1 32100 1360 38727685 Oct 1 18:46 installserver
-rwxr-xr-x 1 32100 1360 5069 Aug 1 2005 server.ini
</code>
Resolution
The installer scripts should have more restrictive default permissions, also the installserver.txt file should be moved inside of the ismp001 directory that is created during installation. Credit
Larry W. Cashdollar http://vapid.dhs.org