-=[!]=-

HITB 2011 Amsterdam Round Two Quals Binary

2011-04-09T23:38:00.001Z

The provided binary is a ELF file designed to be run by inetd and accepts several character based commands followed by their parameters. The main loop reads a character from STDIN (in inetd a socket is duplicated into standard I/O descriptors) and based on the value picks a handler from an array of function pointers. The following commands exist:

'f' - return meta data for a given file name
'l' - list filenames from the home directory
'q' - terminate the process
's' - return symbolic link's path name
'v' - verify input with a key file's data

After mapping out all the available handlers and reviewing how they work there were no obvious vulnerabilities (e.g. buffer overflow). The handler functions that expect additional input first allocate some heap-based memory to store this input and care is taken to make sure it's not overflowed. After the handler completes its work the memory is freed. However, there's a design flaw in the way allocated memory is used when the key text is verified. Specifically, the key data is read into a allocated buffer and compared to the string supplied by a user. Once this is done the memory is simply freed, which returns the memory block to the free pool still containing the key data.

As a result, we can use another handler, which allocates memory for its operation and returns the results to the user. One such command is the 's' character, which accepts a symbolic link as a parameter. Additionally, after listing the contents of the home directory using the 'l' command we find few symbolic links that can be used for the 's' command. Thus, when requesting to view a symbolic link the real path will be copied to a allocated buffer. Since the buffer will come from the free pool and the contents were not cleared then whatever data was there will also be displayed. If the resulting path is shorter in length than the data size of the "KeyFile" we can disclose part of the secret key string.

Looking at the handler for the 'v' command it was identified that a string comparison is performed only on the last 14 bytes of the key file. This tells us how much of the disclosed key file's data we need to grab. Thus, to reproduce we need to submit the 'v' command with any key, which stores the key data into a buffer, but does not clear it after the comparison. Then, submit the 's' command to display the path of the "t1" link, which is short enough to disclose more than 14 bytes of the key file. Finally, take the last 14 bytes and submit them via the 'v' command again and this time the comparison succeeds and gives us the solution key.

The solution string is (w/o quotes): "DwightIzK00l"

Codegate 2011 Quals - Binary 300

2011-03-07T23:44:00.001Z

The question is:

Find a malicious ID!!

The binary is a Browser Helper Object (BHO) DLL with a static XOR key "securecodegate", which is used to decrypt few arrays with statically assigned characters to each index. The "sub_1000233E" function is called with the array and a XOR key as input to perform the decryption. This occurs three times within a handler function "sub_1000270A".

The first two calls are irrelevant as they result in decryption of "google_ads_frame" (key "secure") and "client" (key "code"). However, the third call produces the answer string using the "gate" key.

This was identified by looking for various interesting strings in the binary and locating their use references. The XOR decryption routine is fairly simple and can be performed via a IDC script.

We used a lazy/simple option. Register the DLL ("regsvr32 b300.dll"). Launch Internet Explorer, attach a debugger, locate the handler function ("sub_1000270A"). Modify EIP to jump to the buffer initialization sequence, which is right before the decryption function call (e.g. @ 0x10002C96 for the "gate" key).

The answer is:

ca-pub-0123456789012345

Codegate 2011 Quals - Binary 200

2011-03-07T23:31:00.002Z

The question is:

Reverse Me!!

The binary is a console based PE file. Running the file produces no output due to a certain routine terminating the process before the "main()" function starts. Looking around the code the "sub_401130" function stands out due to initialization of a local array with various bytes. At the end of this function a decryption routine is called ("sub_401070") with the array as input. The decryption loop performs an XOR operation using the string's length as the key.

To obtain the answer a breakpoint was placed @ 0x00401494, which calls the "ExitProcess()" library function prior to "main()". Next, modify EIP to point to the start of the array initialization routine and execute until the decryption function is called. Let it do its XOR job and look at a local buffer once complete to get the answer string.

The answer is:

http://forensic-proof.com/archives/552

Codegate 2011 Quals - Forensics 300

2011-03-07T23:21:00.002Z

The question is:

we are investigating the military secret's leaking. we found traffic with leaking secrets while monitoring the network. Security team was sent to investigate, immediately. But, there was no one present. It was found by forensics team that all the leaked secrets were completely deleted by wiping tool. And the team has found a leaked trace using potable device. Before long, the suspect was detained. But he denies allegations.

Now, the investigation is focused on potable device. The given files are acquired registry files from system. The estimated time of the incident is Mon, 21 February 2011 15:24:28(KST). Find a trace of portable device used for the incident.

The Key : "Vendor name" + "volume name" + "serial number" (please write in capitals)

Enumerate a timeline of USB activity from the backup system hive

...
Disk&Ven_Corsair&Prod_UFD&Rev_0.00,Thu Feb 17 04:41:02 2011,ddf08fb7a86075&0,Thu Feb 17 04:41:03 2011,Corsair UFD USB Device,
Disk&Ven_FM&Prod_Memorette_Swing&Rev_1.00,Thu Feb 17 06:38:21 2011,2008090256000000000000BE&0,Thu Feb 17 06:38:22 2011,FM Memorette Swing USB Device,
...

The enumeration shows all of the USB devices ever connected to the system. The registry last modified times are written the first time the device is connected, but are not updated when a device is subsequently connected.

Running a timeline on the registry (via "regripper"), we see that only one USB device is connected on Feb 21:

Mon Feb 21 06:24:21 2011Z HKLM\ControlSet001\Enum\WpdBusEnumRoot\UMB\2&37c186b&0&STORAGE#VOLUME#_??_USBSTOR#DISK&VEN_CORSAIR&PROD_UFD&REV_0.00#DDF08FB7A86075&0#\Properties\{80d81ea6-7473-4b0c-8216-efc11a2c4c8b}

From there, we know that the suspect device vendor is "CORSAIR" and the serial number of the device is "DDF08FB7A86075". Inspection of this registry path reveals that the default name of the device has been changed. The registry key "FriendlyName" has a value of "PR0N33R", which is the displayed volume name when the device is connected.

The answer is:

CORSAIRPR0N33RDDF08FB7A86075

Thanks to our team member tina for the solution.

Codegate 2011 Quals - Network 100

2011-03-07T22:50:00.002Z

The question is:

This data is related to any attack.
calculate the md5sum of the intended file.

(calc md5 uppercase)

The provided binary is a PCAP file containing bunch of HTTP traffic and some SMB chatter. The question mentions an attack. Since it's heavy on HTTP usage then it made sense to get a list of all requests. Two strange requests stand out:

GET /H1A1.html HTTP/1.1
GET /H1A1.exe HTTP/1.1

Carving out (using Wireshark's "Follow TCP Stream" -> "Save As") the "H1A1.exe" response and removing the HTTP response header we end up with a regular PE file. Next, calculate its MD5 checksum and convert to upper case.

The answer is:

7A5807A5144369965223903CB643C60E

The Manifesto

2010-05-26T20:32:00.004Z

+++The Mentor+++
Written January 8, 1986

Another one got caught today, it's all over the papers. "Teenager Arrested in Computer Crime Scandal", "Hacker Arrested after Bank Tampering"...

Damn kids. They're all alike.

But did you, in your three-piece psychology and 1950's technobrain, ever take a look behind the eyes of the hacker? Did you ever wonder what made him tick, what forces shaped him, what may have molded him?

I am a hacker, enter my world...

Mine is a world that begins with school... I'm smarter than most of the other kids, this crap they teach us bores me...

Damn underachiever. They're all alike.

I'm in junior high or high school. I've listened to teachers explain for the fifteenth time how to reduce a fraction. I understand it. "No, Ms. Smith, I didn't show my work. I did it in my head..."

Damn kid. Probably copied it. They're all alike.

I made a discovery today. I found a computer. Wait a second, this is cool. It does what I want it to. If it makes a mistake, it's because I screwed it up. Not because it doesn't like me... Or feels threatened by me.. Or thinks I'm a smart ass.. Or doesn't like teaching and shouldn't be here...

Damn kid. All he does is play games. They're all alike.

And then it happened... a door opened to a world... rushing through the phone line like heroin through an addict's veins, an electronic pulse is sent out, a refuge from the day-to-day incompetencies is sought... a board is found. "This is it... this is where I belong..." I know everyone here... even if I've never met them, never talked to them, may never hear from them again... I know you all...

Damn kid. Tying up the phone line again. They're all alike...

You bet your ass we're all alike... we've been spoon-fed baby food at school when we hungered for steak... the bits of meat that you did let slip through were pre-chewed and tasteless. We've been dominated by sadists, or ignored by the apathetic. The few that had something to teach found us willing pupils, but those few are like drops of water in the desert.

This is our world now... the world of the electron and the switch, the beauty of the baud. We make use of a service already existing without paying for what could be dirt-cheap if it wasn't run by profiteering gluttons, and you call us criminals. We explore... and you call us criminals. We seek after knowledge... and you call us criminals. We exist without skin color, without nationality, without religious bias... and you call us criminals. You build atomic bombs, you wage wars, you murder, cheat, and lie to us and try to make us believe it's for our own good, yet we're the criminals.

Yes, I am a criminal. My crime is that of curiosity. My crime is that of judging people by what they say and think, not what they look like. My crime is that of outsmarting you, something that you will never forgive me for.

I am a hacker, and this is my manifesto. You may stop this individual, but you can't stop us all... after all, we're all alike.

BIND 9 Dynamic Update DoS

2009-08-06T15:48:00.002Z

Vulnerability described in CVE-2009-0696 is very easy to exploit and the consequences can be disastrous.

All it takes is a singled DNS UDP packet with Dynamic Update structure specially crafted for any Zone which the target server is Master and the named process will exit.

As stated by ISC BIND's update ACLs do not mitigate this vulnerability. Since this is UDP then source IPs can be spoofed and nearly impossible to track down. Even DNS infrastructures which are designed to expose only slave servers to the Internet can be vulnerable if any of them have Master Zones for netblocks mentioned in RFCs 1912 Section 4.1 and 1918 Section 3.

Anyone who wishes to audit their environment can utilize the following Python script. Make sure you have permission to test your targets!.

Given the criticality of this vulnerability several IDS vendors have released detection signatures. However, as of this writing the above script evades the following signatures: Sourcefire and Emerging Threats. Both groups will be notified with necessary information.

milw0rm is gone

2009-07-08T16:00:00.003Z

This was on the site before it went down:

Well, this is my goodbye header for milw0rm. I wish I had the time I did in the past to post exploits, I just don’t :(. For the past 3 months I have actually done a pretty crappy job of getting peoples work out fast enough to be proud of, 0 to 72 hours (taking off weekends) isn’t fair to the authors on this site. I appreciate and thank everyone for their support in the past.
Be safe, /str0ke

PS: I'm keeping their link here for historical reasons.

Tornado exploit pack

2009-05-29T04:41:00.007Z

Like most other exploit packs it's written in PHP with a MySQL backend. Control panel supports configuration options for several users (attackers).

Has the ability to control incoming traffic. It can either:

- Ignore
- Redirect
- Display custom page

based on several criteria such as:

- Country of origin
- Visitor uniqueness
- Vulnerable client
- Not vulnerable client

Displays several different statistics based on:

- Victim's Country
- Originating web site (referer)
- Exploits used
- Detailed Log (IP, time, browser, exploit used, infected (yes/no), and referer)
- Overall Summary - OS and Browser breakd down of traffic and exploit effectiveness

Exploit is delivered in the form of obfuscated javascript. Obfuscated ASCII encoded code and decryption function are delivered to the client as a single long line. This content is unique on every visit except certain parts of the decryption routine. Upon successful exploitation another request will be made to the exploit server to a different script which will deliver the binary to execute.

The following is a list of exploits available to the attacker, which can be individually selected to target:

- MDAC (RDS)
- WebViewFolderIcon.SetSlice
- VML
- MS06-044
- WMF Firefox
- WMF Opera 7
- QuickTime
- WinZip
- Zenturi
- Yahoo Webcam
- Opera 9 - 9.20
- XML Core Services
- Java bytecode
- ANI

Default script for exploit delivery is "count.php", while individual exploit modules are located in the "exploits/" directory with the following naming convention: "x#.php" where # is the numeric value starting with one (1).

Upon successful exploitation another request will be made to retrieve a binary for execution on victim's computer. By default the requested script will be "getexe.exe" with the following parameters:

?o= integer value to identify attacker
&t= integer value represents time the exploit was generated
&i= integer value represent IP address of victim
&e= integer value represents exploit number used

Following is the schema of the database:

CREATE TABLE `stats1` (
`ip` int(10) unsigned default NULL,
`time` int(10) unsigned default NULL,
`country` tinyint(3) unsigned default NULL,
`browser` tinyint(4) default NULL,
`version` varchar(8) default NULL,
`os` tinyint(4) default NULL,
`refdom` varchar(32) default NULL,
`status` tinyint(4) default NULL,
`loader` tinyint(4) default NULL,
`expl` tinyint(4) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=cp1251;

CREATE TABLE `users` (
`id` smallint(5) unsigned NOT NULL auto_increment,
`user` varchar(16) default NULL,
`pass` varchar(32) default NULL,
`premis` tinytext,
`options` tinytext,
`lasttime` int(10) unsigned default NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=cp1251 AUTO_INCREMENT=1;

Improvements to Zeus

2009-05-23T01:47:00.006Z

Zeus's development is active these days. Below is a table of release dates for each version:

2008/12/20 - 1.2.0.0
2008/12/30 - 1.2.1.0
2009/03/11 - 1.2.2.0
2009/03/28 - 1.2.3.0
2009/04/02 - 1.2.4.0

This change log entry states that during HTTP communication of the Trojan with the C&C server the User-Agent used will be that of system's Internet Explorer. Before, it was a constant string embedded in the binary, which could have raised suspicion or blocked by ISPs.

Zeus / Zbot / Prg / Ntos / Wsnpoem

2009-04-26T16:28:00.005Z

Real name of the trojan package is Zeus. It comes with a PHP based control panel and a Windows executable to build the trojan. Builder's job is to parse a text based config file, encrypt it, and embed some options into the trojan. The builder can also remove the infection from the system.

Main scripts of the control panel are:

"in.php"

Script which controls authentication to the admin panel as well as all reporting and configuration options of the botnet.

"s.php"

This is the script which accepts all communication from the bot client on a compromised computer. Depending on configured options it will either insert the data into a MySQL database, or store inside a seperate directory, or both.

It's responsable for decrypting the POST data and parsing individual stolen records. Basically, this is the main C&C script of the botnet.

Keep in mind that these filenames are not hardcoded anywhere but are only the defaults. If the filename is changed on the server then the bot client must be updated with a new configuration file, which it periodically polls off the server. Typical configuration file will have entries similar to the ones on this screenshot.

Currently, Zeus' build tree is 1.2.x.x which, depending on subversions, will utilize either RC4 encryption or a simpler form of it. Otherwise, the record and configuration structures remain the same between different 1.2.x.x builds. Older versions, prior to 1.2.x.x used a completely different structure and obfuscation method. They contained a unique field in the HTTP headers during C&C communication and thus were easily detected via IDS signatures from Emerging Threats (2003182, 2003183, 2007688, 2008100, 2008326)

So, what can this bot/trojan do?
It has the following abilities:

Credential stealing of FTP and POP3 on any TCP port.

Via a custom build can capture any data.

Capture of HTTP and HTTPS traffic.

Proxy server via Socks 4/4a/5, even if compromised device is behind a NAT.

Screenshot capture of the desktop.

Theft of "Protected Storage" data.

Here's an example how a communication flow between bot/trojan and C&C server will look like.

Unique Pack

2009-02-28T14:31:00.005Z

Exploits for Opera9, Firefox, Internet Explorer 4, 5, 6, and 7. Seperate module to exploit Adobe Reader util.printf() (CVE-2008-2992) vulnerability. Also, includes a module to deliver binaries via social engineering the visitor into accepting the download, similar to Fake AV.

So, what's so unique about it? Nothing really. Perhaps the fact that it obfuscates its PHP code which contains exploits, which isn't difficult to take off. Also, maybe because it doesn't use any parameter passing to scripts via URL, as most other packs do. Here's a summary of some scripts:

"cfg/config.php"

Defines variables for loader and exploit URLs, database credentials, and control panel credentials.

URLs are defined for loader script ("load.php") and Adobe PDF exploit ("pdf.php").

Filename of binary which will be dropped ("1.exe").

Database host, name, credentials. Default DB name is "spl".

Control Panel's script name ("admcp.php"), username, and password (double MD5 hash of real pass). Default user is "root".

"cfg/options.php"

Defines functions and text for 404 page. Functions to identify browser, operating system, country (based on GeoIP), and encoding function to Unicode for Javascript (eg: "%u9090").

"cfg/mod_vparivatel.php"

Configuration variables for social engineering module to convince the user to download the binary, similar to the idea used in RogueAV schemes.

"install.php" or "_install.php"

Database creation script. Will connect to the database with configured credentials and create necessary table.

CREATE TABLE `statistic` (
`id` int(10) NOT NULL auto_increment,
`ip` varchar(15) default NULL,
`os` varchar(30) default NULL,
`br` varchar(30) default NULL,
`country` varchar(2) default '--',
`good` int(1) NOT NULL default '0',
`mv` int(1) NOT NULL default '0',
`refer` varchar(300) NOT NULL,
`date` datetime default '2008-10-01 00:00:00',
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=cp1251 AUTO_INCREMENT=1;

"index.php"

Checks for presence of "install.php" and executes it. If visitor's IP was already logged then aborts with HTTP 200 status but shows a 404 page as defined in the variable of the "cfg/options.php" file.

Identifies country, browser, operating system, referer, IP address and updates the database. Includes "sploit.php" file for exploit generation.

"sploits.php"

Checks if "Unique" name is defined and aborts with 404 message from predefined variable if not defined. Determines the browser and loads appropriate exploit script:
"sploit/op9.php" - Opera
"sploit/ff.php" - Firefox
"sploit/ie7.php" - Internet Explorer 7
"sploit/ie.php" - Internet Explorer 4, 5, or 6.

"load.php"

Reads the executable which was defined in config file and serves it to the user. Updates database column "good" for this connection's IP address.

"pdf.php"

Contains the exploit for Adobe Reader ; CVE-2008-2992 ; util.printf(). Interestingly, the file contains obfuscated PHP script to generate the exploit. It has some protection against people attempting to modify the code and print out the exploit. It reads itself and looks for calls to "print | sprint | echo" and aborts if found. This prevents people from simply modifying the "eval" statement to see the real exploit code.

"vparivatel.php"

Delivers an executable file using social engineering technique similar to RogueAV by convincing the user of a threat or some required update. Messages can be customized per browser, operating system, and country.

Checks if visiting IP was already given a binary using this method and aborts if found.

If GET parameter "?a" is set then delivers the binary otherwise displays a convincing message and redirects back to itself with proper parameter.

Armitage 1.0

2009-01-12T03:11:00.002Z

This is a rather old version dated back to November 2007 but perhaps someone will find this info useful.

On the server side it's driven by PHP with MySQL as the backend. File structure is similar to other packs. One noticable difference in the way statistics are tracked, as all packs track visitors and these numbers are used in marketing of packs.

Armitage has an additional section to calculate how many visitors were actually compromised. Typically this is done by recording how many people request a download of a loader (trojan binary) which means the exploit worked. However, this does not account for the fact that loader may have been blocked on the client due to various defenses. Any pack's job is to deliver an exploit and load some binary and many packs are satisfied with just recording such requests. In Armitage's case it is accomplished by recording an additional request which must be made by this loader. This statistic will represent how many devices have been compromised and have gotten the loader to fully execute and check-in. It is unclear why this decision was made for a generic pack since loaders will now have to be specifically written to perform this check-in function. Such loader was not distributed with the pack itself so it is possible that this was not written for general public.

"config.php"

Contains password variables for admin and guest.

"db.php"

Defines variables needed to establish database connection (host, schema, user, and password).

"install.php"

Establishes a database connection and creates the necessary tables. Once complete shows a link to admin page and required credentials.

"admin.php"

Defines two valid accounts admin and guest. Shows traffic and loads statistics as well as has the ability to upload a new trojan and change passwords.

"index.php"

Defines various functions which identify the visitor based on UAS.

Creates the URL for loader "exe.php" and if GET contains "?ex=" integer then this value will be passed to "exe.php?ex=".

Checks visitor's IP address for previous visits and aborts if one is found. String "^_~" is returned upon abort.

Identifies the browser, the following list is used: Opera, Konqueror, Lynx, Links, Internet Explorer, Netscape, Firefox, Mozilla, Other.

Identifies the OS with the following list: Windows (95, NT 4, 98, ME, 2000, XP, 2003, Vista), Linux, Mac OS, Other.

Identifes the Country based on GeoIP library from visitor's IP address. Geoip files are borrowed from Icepack.

Updates statistics for HTTP Referrer, domain only. Sanitizes the referrer domain to avoid SQL injection.

Updates statistics for Browser, OS, and Country. Inserts visitor's IP address and time of visit.

Exploit is served for Internet Explorer from "e.php", for Opera from "opera.php", and Firefox from "ff.php".

"exe.php"

Second stage of the exploit sequence, which serves the binary file. By default it is "./load/file.exe", but if GET "?ex=" integer was set then file with that value is delivered (eg: "./load/file20.exe"). Identifies the visitor (Browser, OS, Country) and updates "loads" statistics table.

"lds.php"

Identifies the Country based on Geoip of the connection and updates the "ots" (otstuk) statistics table. This is the place where loader's check-in stats are kept.

"e.php"

Serves the MDAC exploit slightly obfuscated. CVE-2006-0003 ; MS06-014 ; MDAC (BD96C556-65A3-11D0-983A-00C04FC29E36). If this fails then will load "bof.php".

"bof.php"

Contains the shellcode for buffer overflow exploits.

Serves the WFI exploit. CVE-2006-3730 ; MS06-057 ; "WebViewFolderIcon.WebViewFolderIcon.1.setSlice()".

At the end display the 404 Not Found page which is fake since real HTTP Status code is still 200 OK.

"ff.php"

Serves exploits for Firefox browsers

"opera.php"

Serves exploits for Opera browsers

PE offsets within malware

2009-01-04T15:19:00.003Z

Building on work mentioned in the previous post couple of more interesting facts were identified. Realizing that implementing the Snort's SO rule may not be feasible in some infrastructures, depending on the design and configuration of the sensors, it would be beneficial to identify most common offsets used by malware and how they compare to legitimate executables.

After reviewing offsets found in an installation of Windows XP SP2 system utilizing 8000 samples, both executable and DLL files, and then comparing with offsets found in malware collected over the last year and a half (450 samples) there were several unique offset identified which were solely used by malware.

As a result of this several regular Snort signatures can be written which will alert on download of binaries which should raise suspicion.

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE under 128)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,<,128,58,relative,little; content:"PE|00 00|"; rawbytes; within:130; sid:62; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 12)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,12,58,relative,little; content:"PE|00 00|"; rawbytes; within:14; sid:53; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 16)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,16,58,relative,little; content:"PE|00 00|"; rawbytes; within:18; sid:54; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 64)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,64,58,relative,little; content:"PE|00 00|"; rawbytes; within:66; sid:55; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 96)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,96,58,relative,little; content:"PE|00 00|"; rawbytes; within:98; sid:56; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 124)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,124,58,relative,little; content:"PE|00 00|"; rawbytes; within:128; sid:57; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 144)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,144,58,relative,little; content:"PE|00 00|"; rawbytes; within:146; sid:58; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 152)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,152,58,relative,little; content:"PE|00 00|"; rawbytes; within:154; sid:59; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 160)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,160,58,relative,little; content:"PE|00 00|"; rawbytes; within:162; sid:60; rev:1;)

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"LOCAL Suspicious Executable (PE offset 512)"; flow:established,from_server; content:"MZ"; rawbytes; byte_test:4,=,512,58,relative,little; content:"PE|00 00|"; rawbytes; within:514; sid:61; rev:1;)

Couple of interesting and important notes. There was not a single legitimate binary which contained a PE offset under 128 bytes. The offsets in malware which did not match those of legitimate files occured in %25 of malicious samples.

All offsets found:

Suspicious PE offsets (malware of 467 samples):
-----------------------------------------------
12, 16, 64, 96, 124, 144, 152, 160, 512

Legitimate PE offsets (XP Sp2 8582 samples):
--------------------------------------------
128, 168, 176, 184, 192, 200, 208, 216, 224, 232, 240, 248, 256, 264, 272, 280, 288, 296, 304, 312, 320, 336, 344, 392, 584, 592, 600, 608, 616, 624, 632, 1024, 7680

Detecting packed/crypted executables with Snort

2008-11-16T03:17:00.005Z

As a result of some research into various trojans it was identified that majority of them rely on packers, crypters, and anti debugging tricks. Nothing new here. However, what was interesting is that some of them were completely missed by Snort. Rulebase included default signatures that come with base installation, community rules, and Emerging Threats (ET).

It turns out that analyzed trojans modified the executable's header which did not fall within signature's patterns. This can be partly fixed by creating a signature to detect the PE header's magic value within a certain distance from the start of the DOS header. However, the trick here is to pick a distance which will not produce false negatives. If it's too short then it's doomed to miss lots of stuff. Higher values may produce false positives, more research into this is needed.

It's best to detect executables by reading their structure. PE/COFF format states that the offset to start of PE header is found 0x3C bytes from start of DOS header. I was not able to achieve desired results using the regular Snort rule syntax but using the dynamic rules feature worked perfectly. It's written C and must be compiled. Download it here.

Importance of verifying vendor's protection claims

2008-10-26T17:59:00.003Z

One of my favorite fundamental security principles is perfectly summarized by this blog post: "Are you Secure? Prove it.

This is true for any situation more so for high severity issues like the MS08-067 vulnerability. So, one of the big names in enterprise security products came out with couple of signatures in their end user protection product. I won't name which one since it doesn't really matter in this context.

Taking into account that not all organizations can patch immediately, in large enterprises there are many factors which can contribute to the delay, the last resort to protect users is to rely on security software on their workstations. Antivirus can only go so far and it's largely useless these days. However, some HIPS signatures can limit the exposure.

So, this HIPS product rolled out signatures to supposedly detect and prevent the attack. After testing their claims it turned out that it only blocks exploit attempts from the workstation which has this HIPS installed. Any attacks against this workstation will be successful. It is beyond me why this decision was made. It'll stop the worm from spreding but it won't protect the client from being infected by the trojan which can easily be downloaded by the shellcode.

Interestingly, the response from the vendor was that they created detection for the most common exploit vector. I understand that it's not always possible to create signatures for the vulnerability, product has its limitations, thus only specific exploit vectors are detected.

But in this case it wasn't event the most common vector. My tests used the code which was published on milw0rm by stephenl and at that time had just over 10,000 views, currently at over 16,000. I would think that the vector used in that PoC would be the most common since it's quickly copied by many other hacking sites.

Thus, if organizations rely on their security vendor's claims and don't have in-house expertise to verify those claims then they're at a high risk of having a false sense of security. Considering that this product is from a rather large security vendor then the list of those organizations is rather large.

On the upside, vendor was notified and is currently working on updating their detection.

Neosploit devel/updates retired! However...

2008-08-27T04:35:00.003Z

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.

le fiesta - another exploit pack

2008-08-23T06:07:00.002Z

This is yet another web based exploit pack which utilizes PHP and SQL. Overall, it's similar to the other PHP based packs except here the file structure is much more compact, not that it really matters, and it's less smart about serving out exploits (not loaders) to already visited victims.

Uses two layers of encryption/obfuscation via Javascript with random function and variable names upon each visit. Here's a rough list of included exploits:

COM objects
(see metasploit)

"?spl=com"
EC444CB6-3E7E-4865-B1C3-0DE72EF39B3F CreateControlRange

"?spl=vml2"
DirectAnimation.PathControl

"?spl=wfi"
WebViewFolderIcon.WebViewFolderIcon.1 setSlice()

"?spl=zango1"
8C875948-9C60-4381-9248-0DF180542D53 DownloadAndExec()

"?spl=zango2"
BFC08CFF-C737-4433-BD5A-0EE7EFCFEE54 DownloadAndExec()

"?spl=myspace"
48DD0448-9209-4F81-9F6D-D83562940134

"?spl=ymj"
5F810AFC-BB5F-4416-BE63-E01DD117BD6C AddImage()

"?spl=buddy"
Sb.SuperBuddy.1 LinkSBIcons()

The ?spl= parameter will be passed to "load.php" which will update statistics of each exploit.

"Army cyber ops"...

2008-08-22T02:50:00.003Z

In a Government Computer News article there was an interesting fact mentioned which hints at Army's cyber command centers ability to handle contigency issues.

It was stated that many of their links utilize undersea cables but some also use land based fiber. One of such land links was severed by a garbage truck, disabling service to their northern and southern continental CC for several hours.

Now, I know how difficult it can be to design and run a full contigency operation but one would think that with the budget and resources of a government such a goal should not pose too much of a problem. Apparently, this is not so for Army's cyber ops.

To be honest, it's a big surprise to me. I've seen companies not lose a single tcp connection upon core router/switch failures, cable cuts in server racks, and power outages in data centers and they don't have the same resources as the government can afford.

This isn't a good sign especially in light of more and more talk regarding large scale cyber warefare. Hopefuly, that garbage truck incident served as a lesson. On a bright side, at least the guys at the monitoring consoles got a decent break :)

Why I love cons...

2008-08-16T04:41:00.003Z

Some great talks, interesting presentations and new ideas. Also, you get to meet very interesting people and get to pick their brains or just hang out and enjoy their strange and wonderful personalities.

However, the best is when you discover people who are true hackers. By that I mean people with a certain state of mind who take a creative approach to solve problems.

Here's an example which proves that a real hacker does not need a computer but only his brain:

And yes, this guy was hacking away at deciphering some message.

Analysis of the Adobe exploit within Neosploit

2008-05-24T03:32:00.007Z

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

2008-05-20T19:26:00.002Z

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

2008-05-13T04:23:00.004Z

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

2008-03-15T02:43:00.013Z

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

Adpack analysis

2008-03-08T03:50:00.005Z

Adpack stands for "Advanced Pack" and was written in PHP on the server side along with SQL backend for tracking and statistics.
Analysis was performed on a toolkit which had file timestamps of September 2007.
The pack attempts to exploit the following vulnerabilities:
- MS06-014 (MDAC)
- Java ByteVerify
- Opera 9 (?)

URLs as seen by the victim:

"index.php" - collects statistics and serves the obfuscated Javascript.
"index.php?java" - returns HTML page to load Java applet.
"java.php" - returns a JAR archive for the Java exploit.
"load.php" - returns an Executable file (default: "load.exe").

Details on server side execution of PHP:

"load.php"

Inserts victim's IP address into the database under the compormised table ("ips2").
If unable to INSERT then returns plain text string: "ai siktir vee?".
Increment the "loads" count.
Return an executable file ("load.exe") with MIME type: "application/octet-stream".

"index.php"

Check if configured to serve the Java exploit and URL parameter contains a request for it, and
IP address already visited this script (to get the redirect), and IP address has not been exploited,
only then serve the <applet> tag.

Insert IP address into the database under visitors table ("ips"). If IP address already exists the update will fail.
Failure to INSERT will abort the script and return the same string as for "load.php".

Increment statistical counts for Browser, Operating System, and Country.
The following browser strings are tracked:
"MSIE 7", "MSIE", "Nav", "Lynx", "Bot", "Firefox", "Mozilla".
Following is a list of Operating System strings which is tracked:
"Windows 95", "Windows NT 4", "Win 9x 4.9", "Windows 98", "Windows NT 5.0", "Linux",
"SV1" (as WinXPsp2), "Windows NT 5.1", "Windows NT 5.2", "FreeBSD", "Gentoo", "Ubuntu"

Uses the GeoIP library to identify visitor's country.
Stores the Referer's FQDN field and increments its count.

Passes control (include) to "exploits.php" which serves the Javascript.

"exploits.php"

Defines the Javascript's obfuscation code and the URL used to obtain the Executable file.
By default URL resides in the same directory as the "index.php" script and will be called

"load.php"

Javascript obfuscation function is a simple static single byte XOR routine.

If Java exploit was requested then serve the HTML applet tag with JAR archive as "java.php",
class to run "BaaaaBaa.class" and a single parameter "url" with value of the URL for the Executable.

OR, if browser is "MSIE" then return the obfuscated HTML page.
HEAD will contain a 3 second redirection timeout to the Java exploit URL ("index.php?java").
Rest is Javascript code for the MDAC (MS06-014) exploit.

OR, if browser is "Opera" serve an Opera exploit which will reconfigure a preference for the
TN3270 handler to execute the downloaded Executable file.

"mysql.php"

Connects to the database as defined in "config.php".
Contains definitions for various functions which are used by the toolkit.
:) - contains a blind SQL Injection vulnerability.

"install.php"

Creates the necessary tables in the database. If tables already exists they will be dropped.

"config.php"

Contains the Database configuration and credentials, pack's admin credentials, name of the Executable file.
Boolean toggle for Java exploit.

"admin.php"

Admin page which displays various statistics and allows to reset statistics.
Requires authentication.