IBM Informix (IDS) V10.0 File Clobbering during Install

10/1/2006
Overview
>From the Website (http://www-306.ibm.com/software/data/informix/ids/)

"IBM Informix(r) 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 unpriviledged user can symlink this file
to another file causing the target file have the contents of
installserver.txt appened to it.

vapid:/tmp# ls -l /tmp/installserver.txt
lrwxrwxrwx  1 auditor auditor 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 unpriviledged user can take advantage of an installation by a
priviledged 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

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