Analysis by: Rommel Abraham Joven

ALIASES:

Win32/Glupteba.M(ESET); Fortinet W32/Glupteba.M!tr(Fortinet); Trojan:Win32/Carberp.I(Microsoft); Artemis!C7E32E5BC0DA(McAfee); Trojan.Agent.ED(Malwarebytes)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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.

  TECHNICAL DETAILS

File Size: 111,104 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 May 2015
Payload: Connects to URLs/IPs, Downloads files

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

  • MD7H82HHF7EH2D73

Other System Modifications

This backdoor adds the following registry keys:

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 "21150503"}

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 the value on the previously added registry:
  • {value}, which is the version; and {svalue}, which is the encrypted C&C list
  • Download and execute a file from URL

Download Routine

This backdoor connects to the following URL(s) to download its component file(s):

  • {BLOCKED}.{BLOCKED}.96.102:37174
  • {BLOCKED}.{BLOCKED}.201.43:17659
  • {BLOCKED}.{BLOCKED}.208.82:45297
  • {BLOCKED}.{BLOCKED}.224.26:32136
  • {BLOCKED}.{BLOCKED}.42.114:25127
  • {BLOCKED}.{BLOCKED}.52.26:23097
  • {BLOCKED}.{BLOCKED}.163.194:60098
  • {BLOCKED}.{BLOCKED}.103.78:36034
  • {BLOCKED}.{BLOCKED}.160.173:12131
  • {BLOCKED}.{BLOCKED}.253.1:22357
  • {BLOCKED}.{BLOCKED}.7.65:21903
  • {BLOCKED}.{BLOCKED}.19.171:57136
  • {BLOCKED}.{BLOCKED}.96.151:31993
  • {BLOCKED}.{BLOCKED}.98.2:49891
  • {BLOCKED}.{BLOCKED}.36.128:15206
  • {BLOCKED}.{BLOCKED}.56.247:11754
  • {BLOCKED}.{BLOCKED}.140.15:16577
  • {BLOCKED}.{BLOCKED}.22.66:22740
  • {BLOCKED}.{BLOCKED}.31.250:38102
  • {BLOCKED}.{BLOCKED}.55.90:45297
  • {BLOCKED}.{BLOCKED}.56.202:45297
  • {BLOCKED}.{BLOCKED}.205.155:22887
  • {BLOCKED}.{BLOCKED}.205.163:25549
  • {BLOCKED}.{BLOCKED}.148.43:49126
  • {BLOCKED}.{BLOCKED}.237.81:19413
  • {BLOCKED}.{BLOCKED}.105.138:38109
  • {BLOCKED}.{BLOCKED}.167.242:15745
  • {BLOCKED}.{BLOCKED}.84.82:35971
  • {BLOCKED}.{BLOCKED}.79.158:58186
  • {BLOCKED}.{BLOCKED}.79.200:33879
  • {BLOCKED}.{BLOCKED}.73.175:58186
  • {BLOCKED}.{BLOCKED}.71.36:22508
  • {BLOCKED}.{BLOCKED}.208.11:32965
  • {BLOCKED}.{BLOCKED}.189.121:26195
  • {BLOCKED}.{BLOCKED}.177.4:18532
  • {BLOCKED}.{BLOCKED}.103.43:58207
  • {BLOCKED}.{BLOCKED}.59.2:26195
  • {BLOCKED}.{BLOCKED}.138.226:31973
  • {BLOCKED}.{BLOCKED}.66.66:45297
  • {BLOCKED}.{BLOCKED}.78.26:52112
  • {BLOCKED}.{BLOCKED}.58.68:23480
  • {BLOCKED}.{BLOCKED}.192.230:26666
  • {BLOCKED}.{BLOCKED}.108.1:40015
  • {BLOCKED}.{BLOCKED}.150.2:33376
  • {BLOCKED}.{BLOCKED}.192.31:25905
  • {BLOCKED}.{BLOCKED}.99.100:30124
  • {BLOCKED}.{BLOCKED}.137.149:23099
  • {BLOCKED}.{BLOCKED}.200.157:52112
  • {BLOCKED}.{BLOCKED}.37.210:49994
  • {BLOCKED}.{BLOCKED}.117.197:28171
  • {BLOCKED}.{BLOCKED}.188.2:48105
  • {BLOCKED}.{BLOCKED}.24.234:45297
  • {BLOCKED}.{BLOCKED}.87.184:49205
  • {BLOCKED}.{BLOCKED}.115.196:21196
  • {BLOCKED}.{BLOCKED}.218.14:45570
  • {BLOCKED}.{BLOCKED}.80.46:25127
  • {BLOCKED}.{BLOCKED}.113.81:10934
  • {BLOCKED}.{BLOCKED}.212.34:51447
  • {BLOCKED}.{BLOCKED}.67.170:53872
  • {BLOCKED}.{BLOCKED}.77.28:27190
  • {BLOCKED}.{BLOCKED}.180.232:53872
  • {BLOCKED}.{BLOCKED}.180.243:33879
  • {BLOCKED}.{BLOCKED}.181.123:27571
  • {BLOCKED}.{BLOCKED}.67.39:24247
  • {BLOCKED}.{BLOCKED}.154.220:53818
  • {BLOCKED}.{BLOCKED}.56.90:10703
  • {BLOCKED}.{BLOCKED}.1.90:11982
  • {BLOCKED}.{BLOCKED}.1.171:22459
  • {BLOCKED}.{BLOCKED}.223.12:49116
  • {BLOCKED}.{BLOCKED}.107.132:19796
  • {BLOCKED}.{BLOCKED}.11.117:20357
  • {BLOCKED}.{BLOCKED}.104.139:18532
  • {BLOCKED}.{BLOCKED}.209.207:53127
  • {BLOCKED}.{BLOCKED}.209.137:37127
  • {BLOCKED}.{BLOCKED}.231.223:43992
  • {BLOCKED}.{BLOCKED}.110.162:37174
  • {BLOCKED}.{BLOCKED}.85.118:49126
  • {BLOCKED}.{BLOCKED}.118.22:48439
  • {BLOCKED}.{BLOCKED}.118.90:35535
  • {BLOCKED}.{BLOCKED}.70.56:38271
  • {BLOCKED}.{BLOCKED}.20.226:54127
  • {BLOCKED}.{BLOCKED}.59.99:30577
  • {BLOCKED}.{BLOCKED}.132.233:39353
  • {BLOCKED}.{BLOCKED}.119.1:35535
  • {BLOCKED}.{BLOCKED}.151.109:54091
  • {BLOCKED}.{BLOCKED}.138.200:18150
  • {BLOCKED}.{BLOCKED}.134.140:19753
  • {BLOCKED}.{BLOCKED}.77.246:51841
  • {BLOCKED}.{BLOCKED}.45.29:22237
  • {BLOCKED}.{BLOCKED}.20.202:36102
  • {BLOCKED}.{BLOCKED}.188.250:48439
  • {BLOCKED}.{BLOCKED}.195.47:59899
  • {BLOCKED}.{BLOCKED}.41.63:49996
  • {BLOCKED}.{BLOCKED}.223.98:53127
  • {BLOCKED}.{BLOCKED}.146.114:27042
  • {BLOCKED}.{BLOCKED}.133.248:46856

It saves the files it downloads using the following names:

  • %User Temp%\nvu{random}.tmp.exe - it executes this file

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

NOTES:

This backdoor notifies the IP addresses mentioned above by sending the following HTTP GET request, and then waiting for further acknowledgement before downloading:

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

However, as of this writing the request attempts fail.

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

The following are the websites accessed when users click on the link or the photo:

  • https://www.{BLOCKED}crush.com
  • https://www.{BLOCKED}ok.xxx
  • https://www.{BLOCKED}t.net

  SOLUTION

Minimum Scan Engine: 9.700

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

Restart in Safe Mode

[ Learn More ]

Step 4

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 5

Search and delete these files

[ Learn More ]
There may be some files that are 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.  
  • %User Temp%\nvu{random}.tmp.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_GLUPTEBA.YVA. 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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