Analysis by: Mar Philip Elaurza
ALIASES:

Trojan-Proxy.Win32.Glupteba.nft (Kaspersky), Trojan:Win32/Bagsu!rfn (Microsoft), SAPE.Heur.879f (Symantec),

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 284,858 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Oct 2015
Payload: Connects to URLs/IPs

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor drops the following copies of itself into the affected system and executes them:

  • %AppDataLocal%\NVIDA Corporation\Updates\NvdUpd.exe

(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • MD7H82HHF7EH2D73

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
NvUpdSrv = %AppDataLocal%\NVIDIA Corporation\Updates\NvdUpd.exe

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\NVIDIA Corporation

HKEY_CURRENT_USER\Software\NVIDIA Corporation\
Global

HKEY_CURRENT_USER\Software\NVIDIA Corporation\
Global\nvUpdSrv

It adds the following registry entries:

HKEY_CURRENT_USER\Software\NVIDIA Corporation\
Global\nvUpdSrv
value = {installed version of malware which is "21150727"}

HKEY_CURRENT_USER\Software\NVIDIA Corporation\
Global\nvUpdSrv
GUID = {GUID}

HKEY_CURRENT_USER\Software\NVIDIA Corporation\
Global\nvUpdSrv
svalue = {random characters}

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Creates a proxy connection
  • Gather information from past created proxy connection
  • Close socket of proxy connection
  • Modify its added registry entries value and svalue
  • Download and execute arbitrary file

It connects to the following websites to send and receive information:

  • {BLOCKED}.{BLOCKED}.97.157:58186
  • {BLOCKED}.{BLOCKED}.200.153:17513
  • {BLOCKED}.{BLOCKED}.227.210:45297
  • {BLOCKED}.{BLOCKED}.14.98:51917
  • {BLOCKED}.{BLOCKED}.243.115:25603
  • {BLOCKED}.{BLOCKED}.176.249:52112
  • {BLOCKED}.{BLOCKED}.150.34:38862
  • {BLOCKED}.{BLOCKED}.160.173:12131
  • {BLOCKED}.{BLOCKED}.253.1:22357
  • {BLOCKED}.{BLOCKED}.201.53:20075
  • {BLOCKED}.{BLOCKED}.130.17:11263
  • {BLOCKED}.{BLOCKED}.98.2:51376
  • {BLOCKED}.{BLOCKED}.223.4:57578
  • {BLOCKED}.{BLOCKED}.36.128:15206
  • {BLOCKED}.{BLOCKED}.36.253:51376
  • {BLOCKED}.{BLOCKED}.66.242:27042
  • {BLOCKED}.{BLOCKED}.55.90:45297
  • {BLOCKED}.{BLOCKED}.59.146:45297
  • {BLOCKED}.{BLOCKED}.25.185:59981
  • {BLOCKED}.{BLOCKED}.21.1:33679
  • {BLOCKED}.{BLOCKED}.48.8:37007
  • {BLOCKED}.{BLOCKED}.94.44:31588
  • {BLOCKED}.{BLOCKED}.10.194:34409
  • {BLOCKED}.{BLOCKED}.131.170:45370
  • {BLOCKED}.{BLOCKED}.167.242:15745
  • {BLOCKED}.{BLOCKED}.33.126:42386
  • {BLOCKED}.{BLOCKED}.138.38:51376
  • {BLOCKED}.{BLOCKED}.57.216:39106
  • {BLOCKED}.{BLOCKED}.216.108:51376
  • {BLOCKED}.{BLOCKED}.125.65:18703
  • {BLOCKED}.{BLOCKED}.242.114:29342
  • {BLOCKED}.{BLOCKED}.71.36:22508
  • {BLOCKED}.{BLOCKED}.208.11:32965
  • {BLOCKED}.{BLOCKED}.189.121:26195
  • {BLOCKED}.{BLOCKED}.196.144:20480
  • {BLOCKED}.{BLOCKED}.25.8:40406
  • {BLOCKED}.{BLOCKED}.103.43:58207
  • {BLOCKED}.{BLOCKED}.147.29:33376
  • {BLOCKED}.{BLOCKED}.73.240:27936
  • {BLOCKED}.{BLOCKED}.66.66:45297
  • {BLOCKED}.{BLOCKED}.204.220:53986
  • {BLOCKED}.{BLOCKED}.141.2:40443
  • {BLOCKED}.{BLOCKED}.69.212:53129
  • {BLOCKED}.{BLOCKED}.78.145:39632
  • {BLOCKED}.{BLOCKED}.58.68:23480
  • {BLOCKED}.{BLOCKED}.90.15:45297
  • {BLOCKED}.{BLOCKED}.49.22:12410
  • {BLOCKED}.{BLOCKED}.151.70:23370
  • {BLOCKED}.{BLOCKED}.210.72:35607
  • {BLOCKED}.{BLOCKED}.37.210:49994
  • {BLOCKED}.{BLOCKED}.56.11:19141
  • {BLOCKED}.{BLOCKED}.119.203:34373
  • {BLOCKED}.{BLOCKED}.2.130:10557
  • {BLOCKED}.{BLOCKED}.74.150:31973
  • {BLOCKED}.{BLOCKED}.87.184:49205
  • {BLOCKED}.{BLOCKED}.251.29:16493
  • {BLOCKED}.{BLOCKED}.130.99:17325
  • {BLOCKED}.{BLOCKED}.216.19:44573
  • {BLOCKED}.{BLOCKED}.80.46:25127
  • {BLOCKED}.{BLOCKED}.211.223:59138
  • {BLOCKED}.{BLOCKED}.114.80:26093
  • {BLOCKED}.{BLOCKED}.113.81:10934
  • {BLOCKED}.{BLOCKED}.119.218:37127
  • {BLOCKED}.{BLOCKED}.233.149:35173
  • {BLOCKED}.{BLOCKED}.171.130:13586
  • {BLOCKED}.{BLOCKED}.77.28:27190
  • {BLOCKED}.{BLOCKED}.53.165:34549
  • {BLOCKED}.{BLOCKED}.39.114:19650
  • {BLOCKED}.{BLOCKED}.54.133:31189
  • {BLOCKED}.{BLOCKED}.154.220:53818
  • {BLOCKED}.{BLOCKED}.224.22:39976
  • {BLOCKED}.{BLOCKED}.27.43:28731
  • {BLOCKED}.{BLOCKED}.56.90:10703
  • {BLOCKED}.{BLOCKED}.62.4:16660
  • {BLOCKED}.{BLOCKED}.88.151:24423
  • {BLOCKED}.{BLOCKED}.11.117:20357
  • {BLOCKED}.{BLOCKED}.229.240:43992
  • {BLOCKED}.{BLOCKED}.188.228:30708
  • {BLOCKED}.{BLOCKED}.240.170:25338
  • {BLOCKED}.{BLOCKED}.102.111:46975
  • {BLOCKED}.{BLOCKED}.85.118:49126
  • {BLOCKED}.{BLOCKED}.241.7:37399
  • {BLOCKED}.{BLOCKED}.70.56:38271
  • {BLOCKED}.{BLOCKED}.183.94:49721
  • {BLOCKED}.{BLOCKED}.175.170:49996
  • {BLOCKED}.{BLOCKED}.119.178:19069
  • {BLOCKED}.{BLOCKED}.119.1:35535
  • {BLOCKED}.{BLOCKED}.175.34:35638
  • {BLOCKED}.{BLOCKED}.138.200:18150
  • {BLOCKED}.{BLOCKED}.77.246:51841
  • {BLOCKED}.{BLOCKED}.252.192:51964
  • {BLOCKED}.{BLOCKED}.40.93:29037
  • {BLOCKED}.{BLOCKED}.0.216:37288
  • {BLOCKED}.{BLOCKED}.35.140:28103
  • {BLOCKED}.{BLOCKED}.41.63:49996
  • {BLOCKED}.{BLOCKED}.172.134:36822
  • {BLOCKED}.{BLOCKED}.222.1:33879
  • {BLOCKED}.{BLOCKED}.203.86:11908
  • {BLOCKED}.{BLOCKED}.208.91:14229
  • {BLOCKED}.{BLOCKED}.246.180:50007
  • {BLOCKED}.{BLOCKED}.246.47:51117
  • {BLOCKED}.{BLOCKED}.171.78:59899
  • {BLOCKED}.{BLOCKED}.133.248:46856

NOTES:

This backdoor notifies the IP addresses mentioned above by sending the following HTTP GET request, and then receives a port number, to which the backdoor will connect to:

  • /stat?uid={value}&downlink={value}&uplink={value}&id={value}&statpass={value}&version={value}&features={value}&guid={value}&comment={value}&p={value}&s={value}

Because this backdoor is capable of creating proxy connections, it is able to use the infected computer as a relay to spam email sent originally by the C&C. The email it sends contains any of the following:

  • A message inviting the reader to check out an online portfolio
  • A link directing users to a dating/adult website
  • An attractive picture that leads to a dating/adult website when users click on the said picture

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.864.05
FIRST VSAPI PATTERN DATE: 19 Aug 2015
VSAPI OPR PATTERN File: 11.865.00
VSAPI OPR PATTERN Date: 20 Aug 2015

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_GLUPTEBA.YVG

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete the files detected as BKDR_GLUPTEBA.YVG

*Note: Some component files may be hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.

To stop the malware/grayware from running when certain files are opened:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Right-click Start then click Search....
  2. In the File name* input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012 (R2):

  1. Open a Windows Explorer window.
    • For Windows Vista, 7, and Server 2008 users, click Start>Computer.
    • For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen,then click File Explorer.
  2. In the Search Computer/This PC input box, type the name of the file that was detected earlier.
  3. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: Read the following Microsoft page if these steps do not work on Windows 7.

Step 6

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • NvUpdSrv = %AppDataLocal%\NVIDIA Corporation\Updates\NvdUpd.exe

Step 7

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\NVIDIA Corporation\Global
    • nvUpdSrv

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_GLUPTEBA.YVG. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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