Neosploit devel/updates retired! However...

It seems that development of this exploit pack has ended. The message basically states that efforts which are put into development are not returning enough income and supported is ending.

However, this does not mean that you will no longer see exploits delivered via this framework. There are many installations of it out there and it's still one of the best exploit packs, although it was expensive. Also, the Neo folks have released instructions/script on how to move the CGI program from one server to another. Previously, this had to be done with the help of Neosploit Support, as the binary was compiled for specific server. If source code is leaked out or released then it's highly likely that more malware will be delivered through it.

Now, that background info behind us, we have seen something interesting which leaves more questions then answers. We have identified a site which utilizes this pack to drop a binary which seems to be associated with the recent fake Antivirus malware.

What is of most interest is the fact that the obfuscated script, mainly the deobfuscation function has some modifications to its code. Several key statements were rearranged in such a way that logic isn't changed.

Why make such a change? Is it a change or some older build which had a short life span and wasn't updated since? We've been keeping an eye on Neosploit's progress for many months now and have never seen this code sequence. We have observed similar minor changes before, during active development, but now since it's supposedly retired the update does stand out. Is it possible that source code was leaked? or did someone just modify the binary in place, and for what purpose, evade detection?

More research is needed to confirm if this change occurs elsewhere, on other domains hosting Neosploit.

Analysis of the Adobe exploit within Neosploit

It appears that currently the toolkit is under active development. Adobe vulnerability which is exploited is one from CVE-2007-5659 disclosure.

We have seen some old exploit being added, removed, then added again. This was the MS06-067 DirectAnimation.PathControl.KeyFrame() vulnerability. More on this one later.

The function which exploits Adobe vulnerability (CVE-2007-5659) will try to load ActiveX controls in the following order:

1. AcroPDF.PDF
2. PDF.PdfCtrl

If successful then it'll identify the version in use and will continue only if it's below 8.1.2, which makes sense since Adobe realeased an unpdate with this version that fixed the issue. Then, the version is inserted into an already embedded URL string to download the actual PDF file.



Returned PDF file is around 10K in size and contains Zlib compressed obfuscated Javascript. Thus, any IDS detection which looks for the vulnerable code will not pick this one up. Obfuscation method is the same as for all other pages. After peeling this layer off one finds the familiar heap spray function to populate memory with the shellcode. Then, once again a version check is performed. Finally, a long string is created (~ 44K) and used as an argument to Collab.collectEmailInfo() method.



If the overflow works, then the shellcode will GET a URL which is the same as the one before except for one changed byte (from 01 -> 02), perhaps to track which stage is requested. That file is an Executable which will be saved in the user's Temp directory as "sxoC.exe".

For those who rely on HIDS/HIPS, AV, nIDS/nIPS chances are nothing will be seen, unless the dropped binary gets picked up by AV (right!).

Neosploit development update

For the past month or so we have been observing more activity in Neosploit's development. Exploits are being removed then added and new ones introduced. To be fair in relation to the previous post we can now confirm that Adobe exploit IS being used by this toolkit.

Another interesting change is less obvious and not so important to Incident Responders but more so for Intrusion Detection folks. The main Javascript deobfuscation function has seen some changes recently. So, those of you who depend on IDS to detect the script should probably review their traffic, honeypots, hids, etc... for new changes.

Neosploit update and changes

Some interesting changes we have observed:

- URL scheme changed
- Javascript deobfuscation updated
- Vulnerabilities exploited changed

Javascript deobfuscation code has changed a bit. Previously, to get to the actual exploit code one had to go through two decryption stages, this time an additional stage is added to the very first layer. This additional layer does not make a request out to the server.


Basically, upon first visit to the Neosploit site a browser gets one big obfuscated Javascript page. It executes the decryption function which results in another obfuscated javascript layer. This second layer decrypts itself and then runs real javascript of the first stage. This stage adds some encoded parameters to the URL for the second stage.


URL scheme for requests to exploits and binaries has been updated. It appears that a full structure is passed as a parameter to the main script. This struct is hex encoded as a string and uses various flags and variables to track victims and statistics.


Javascript decryption function utilizes the "arguments.callee" trick to convert itself into an uppercase string and use offsets within this string to decrypt the payload. This is the main deobfuscation characteristic of Neosploit. Several changes have been made previously which break down the methods into seperate variables instead of using them directly.


An interesting addition has been included recently, which appends Neosploit's web address to the decoding offset string. Thus, to successfully decrypt the payload the original full address of the script must be known. Also, at the exploit stage there's a function which sets a unique cookie ("ID") with a specific value for a given exploit.


Stage 1

First stage is the initial visit (iframe, redirect, ...) to Neosploit page. At this point a structure is created based on public variables such as the User Agent string and IP address. Then the server returns obfuscated Javascript page, which is dynamically generated with random variables, and contains the first part of the URL for the next stage.

Stage 2

This stage is obfuscated with two layers and then attempts to identify the victim's Service Pack level, and system's language then builds a request string with these parameters to get the second stage. This request URL has a specific argument to the main script. First part is added by the server upon initial visit and consists of various hashed parameters then SP level and language string is appended.

Stage 3
Deobfuscation yields the exploit code for the following vulnerabilities (in exploit order):

- CVE-2006-0003 ; MS06-014 ; MDAC (BD96C556-65A3-11D0-983A-00C04FC29E36)
- CVE-2006-5820 ; "Sb.SuperBuddy.LinkSBIcons()" ; Cookie ID = 9
- CVE-2007-5779 ; "GomWebCtrl.GomManager.1.OpenURL()" ; Cookie ID = 13
- CVE-2008-1472 ; CA BrightStor ArcServe Backup AddColumn() (BF6EFFF3-4558-4C4C-ADAF-A87891C5F3A3) ; Cookie ID = 21
- CVE-????-???? ; "QuickTime.QuickTime.4" ; Cookie ID = 6

PS: Symantec stated that recent Adobe vulnerability was being exploited by this toolkit, however the instance which was analyzed for this post did not include any Adobe exploits.

Neosploit update

For a while now we have been observing version 2.0.15 used by many malicious sites. However, it seems that recently there's been an update to the toolkit.

There were two exploits added, initially reported by Exploit Prevention Labs, and some slight changes in the decryption function of the obfuscated Javascript. Also, minor changes in the URL scheme used to track statistics on visitors and victims.

Here are the vulnerabilities exploited as of today:

"Internet Explorer"

(3) - cve-2007-0018 "NCTAudioFile2" ActiveX control "SetFormatLikeSample()" method (77829F14-D911-40FF-A2F0-D11DB8D6D0BC)
(7) - cve-2006-4777 "DirectAnimatioin.PathControl" ActiveX control "KeyFrame()" method (D7A7D7C3-D47F-11D0-89D3-00A0C90833E6)
(9) - cve-2006-5820 "Sb.SuperBuddy.LinkSBIcons()"
(12) - cve-2006-3730 "WebViewFolderIcon.WebViewFolderIcon.1.setSlice()"
(13) - cve-2007-5779 "GomWebCtrl.GomManager.1.OpenURL()"
(19) - cve-2008-0624 Yahoo! Music Jukebox DataGrid ActiveX control AddButton() method (5F810AFC-BB5F-4416-BE63-E01DD117BD6C)
(20) - cve-2007-2222 MS07-033 Microsoft Speech API ActiveVoice control (EEE78591-FE22-11D0-8BEF-0060081841DE)

"Firefox"

cve-2006-0005 Windows Media Player Plugin MS06-006
cve-2007-0015 QuickTime RTSP Response Header Content-Type

Neosploit server side execution

Toolkit is written in C and runs as a CGI program in the web server. Here are some details about its execution. Data obtained from analysis of version 1.0 of the toolkit. Current versions seen in the wild are 1.5 and 2.0, which may change or add some of the URL schemes.

Exploit URL sequence as seen by the victim:

"?p=user1" - serves the obfuscated Javascript code
"?u2_1_600_2_0_870665223_2792316769_2354152789" - gets the first stage loader (values are not static)
"?l=user" - second stage loader, first stage will contact this URL

*** Populate internal structures ***

Load environment structure obtained from web server's environment variables:
HTTP_USER_AGENT, QUERY_STRING, HTTP_HOST, REQUEST_URI, REMOTE_ADDR, HTTP_COOKIE, SCRIPT_NAME, HTTP_REFERER

Load the form structure obtained from values either in POST or GET request.

Populate statistics structure: Operating System (via UAS), Browser (via UAS), generate hash of referer, userid (toolkit is a multiuser system, this isn't the userid of the victim), Some additional data ("?a=").

Loads the structure with necessary filenames used for statistics and config (starts w/ name of script: "in.cgi")
"in.hits" = Traffic file
"in.loads" = Loads file
"in.loads2" = Loads 2 file
"in.key" = License file
"in.passwd" = Password file (username, passwd, user's configs)
"in.refs" = Referers

*** Generate exploit code and URLs ***

Check if REMOTE_ADDR is in traffic file (.hits). If IP is visiting again within the block time (default 60m) then abort, otherwise serve exploit.

Check if query contains a referenced user ("?p=user") then use his config otherwise default.

Exploit is served based on browser (exploits reside in seperate header files).

Exploitation of Firefox, Netscape, and Opera is configured during toolkit's build time. Internet Explorer is always enabled.

Build a URL to download the loader in format of "%s?u%hu_%hu_%u_%hu_%lu_%lu_%lu_%s": Script name, OS, Browser, Browser Version, Exploit used, additional (??), Hash of REMOTE_ADDR, Hash of HTTP_REFERER, Exploit user.

Shellcode and Loader's URL are inserted into the dynamically generated Javascript code with random variables names and sent to browser.

*** Response to shellcode's request ***

Populate log structure with data taken from GET URL ("?u1_1_10_...")

To get the loader the following conditions must be true: Browser is one of: IE, Firefox, Netscape, Opera; OS is one of: 95, 98, NT, XP, ME, 2k, 2k3 (? Vista); Browser version is set; REMOTE_ADDR is in statistics file ("in.loads") within the block time (IP isn't compared if current time is passed the block time); and the IP's hash in the request URL has to match hash of REMOTE_ADDR.

If unable to open malicious EXE file to send to victim then responds with message: "can't open (pipe stream|file) ${EXE_path}".

Log visitor's IP and time into loader's log ("in.loads").

*** Second stage loader ***

Initial loader may be part of multi-stage loading sequence. If configured as such then first stage loader will callback for the second stage EXE w/ request URL in form: "?l=user".

Check if REMOTE_ADDR is in statistics file ("in.loads") and is within the block time (IP isn't compared if current time is passed the block time). Record IP and time into "in.loads2" file.

If second stage loader exists then serve it.

Neosploit exploit toolkit

The Neosploit toolkit is an advanced exploit framework to compromise web site visitors. It was written by "grabarz". It is unknown if this is a group or an individual. There's some information which suggests it is an individual.

It's not as popular as the Mpack toolkit but is gaining popularity steadily. It was written in the C language and is used as a CGI script. It can support multiple users from the same script. The exploit code will be the same from all users but the delivered executables can be different.

Similar to other toolkits this one provide various statistics too. Instead of using a database as the means to store them Neosploit uses several files with specific internal structures. The following information about the visitor is logged: Operating System, Web browser and its version, IP address, and the Referer.

Delivered exploit code is obfuscated using custom Javascript decoding function. The function name and all local variables are random in order to avoid detection by Network IDS. Often, several layers of obfuscation with anti-decoding tricks are used to deter the faint-hearted.

Toolkit's URL scheme is designed in such a way which will prohibit thecurious of obtaining the executables even if the same one is used from previous exploits.

Perhaps the reason for its slow adoption is its high price. It ranges, depending on version, from $1500 to $3000. Common version seen today in the wild is 1.5.x, with 2.0.x in beta mode. First detected version was 1.0.x early this year.

More in-depth analysis will follow.