BKDR_DYRE.AM

 Analysis by: RonJay Kristoffer Caragay

 ALIASES:

TrojanDownloader:Win32/Upatre (Microsoft); Troj/Upatre-LD (Sophos); Trojan-Downloader.Win32.Upatre.fkvo (Kaspersky)

 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 may be downloaded by other malware/grayware from remote sites.

It uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

It connects to certain websites to send and receive information. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

498,688 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Nov 2015

Payload:

Connects to URLs/IPs

Arrival Details

This backdoor may be downloaded by the following malware/grayware from remote sites:

  • TROJ_UPATRE.YYSQQ

Installation

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

  • %AppDataLocal%\{random filename}.exe (for Windows Vista and above)
  • %Windows%\{random filename}.exe (for Windows XP and below)

(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.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

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

  • Global\{random}

It injects codes into the following process(es):

  • explorer.exe
  • svchost.exe

Autostart Technique

The scheduled task executes the malware every:

  • 1 minute

Other System Modifications

This backdoor modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Lsa
LimitBlankPasswordUse = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server
fDenyTSConnections = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server
fSingleSessionPerUser = "0"

(Note: The default value data of the said registry entry is 1.)

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • Receive configuration(web injects/MitB)
  • Receive New connections
  • Download file and execute
  • Download Module
  • Browser Snapshot
  • Terminate Process
  • Add Users
  • Wipe Master Boot Record (MBR), Drives C and D
  • Reboot system

Dropping Routine

This backdoor drops the following files:

  • %System%\config\systemprofile\Application Data\{random filename} (for Windows XP and below)
  • %AppDataLocal%\{random filename} (for Windows Vista and above)

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %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.)

Information Theft

This backdoor s configuration file contains the following information:

  • List of strings related to banking/bitcoin
  • Proxy address for the Man-in-the-middle attack
  • List of new C&C server

It gathers the following data:

  • Host Name
  • Public IP Address
  • Computer Name
  • OS Version
  • OS Platform
  • User Accounts
  • System Info(CPU, Memory, No. of Processors)
  • Installed programs
  • Services

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

  • google.com
  • microsoft.com

It connects to the following URL(s) to get the affected system's IP address:

  • http://icanhazip.com

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

  • http://{BLOCKED}.{BLOCKED}.1.13:4443
  • http://{BLOCKED}.{BLOCKED}.116.174:443
  • http://{BLOCKED}.{BLOCKED}.212.105:443
  • http://{BLOCKED}.{BLOCKED}.180.41:4443
  • http://{BLOCKED}.{BLOCKED}.69.251:443
  • http://{BLOCKED}.{BLOCKED}.49.11:443
  • http://{BLOCKED}.{BLOCKED}.228.68:4443
  • http://{BLOCKED}.{BLOCKED}.166.94:4443
  • http://{BLOCKED}.{BLOCKED}.50.124:4443
  • http://{BLOCKED}.{BLOCKED}.239.194:443
  • http://{BLOCKED}.{BLOCKED}.101.194:4443
  • http://{BLOCKED}.{BLOCKED}.122.32:443
  • http://{BLOCKED}.{BLOCKED}.109.92:443
  • http://{BLOCKED}.{BLOCKED}.76.17:4443
  • http://{BLOCKED}.{BLOCKED}.217.70:443
  • http://{BLOCKED}.{BLOCKED}.68.104:443
  • http://{BLOCKED}.{BLOCKED}.68.129:443
  • http://{BLOCKED}.{BLOCKED}.9.108:443
  • http://{BLOCKED}.{BLOCKED}.9.141:443
  • http://{BLOCKED}.{BLOCKED}.9.225:443
  • http://{BLOCKED}.{BLOCKED}.167.234:4443
  • http://{BLOCKED}.{BLOCKED}.240.79:4443
  • http://{BLOCKED}.{BLOCKED}.77.76:443
  • http://{BLOCKED}.{BLOCKED}.206.82:443
  • http://{BLOCKED}.{BLOCKED}.207.134:4443
  • http://{BLOCKED}.{BLOCKED}.60.33:443
  • http://{BLOCKED}.{BLOCKED}.67.190:443
  • http://{BLOCKED}.{BLOCKED}.104.166:4443
  • http://{BLOCKED}.{BLOCKED}.240.118:443
  • http://{BLOCKED}.{BLOCKED}.101.2:4443
  • http://{BLOCKED}.{BLOCKED}.108.47:4443
  • http://{BLOCKED}.{BLOCKED}.78.174:443
  • http://{BLOCKED}.{BLOCKED}.200.112:443
  • http://{BLOCKED}.{BLOCKED}.182.109:443
  • http://{BLOCKED}.{BLOCKED}.67.80:443
  • http://{BLOCKED}.{BLOCKED}.28.44:443
  • http://{BLOCKED}.{BLOCKED}.251.162:443
  • http://{BLOCKED}.{BLOCKED}.196.217:443
  • http://{BLOCKED}.{BLOCKED}.208.13:443
  • http://{BLOCKED}.{BLOCKED}.131.116:443
  • http://{BLOCKED}.{BLOCKED}.226.74:443
  • http://{BLOCKED}.{BLOCKED}.71.149:4443
  • http://{BLOCKED}.{BLOCKED}.176.230:4443
  • http://{BLOCKED}.{BLOCKED}.232.18:443
  • http://{BLOCKED}.{BLOCKED}.158.109:443
  • http://{BLOCKED}.{BLOCKED}.48.38:443
  • http://{BLOCKED}.{BLOCKED}.62.195:4443
  • http://{BLOCKED}.{BLOCKED}.47.107:443

It does the following:

  • Monitors the following browsers:
    • chrome.exe
    • chromium.exe
    • firefox.exe
    • iexplore.exe
    • microsoftedge
  • Connects to the following STUN (Session Traversal Utilities for NAT) server in order to determine the public IP address of the compromised computer:
    • stun1.voiceeclipse.net
    • stun.callwithus.com
    • stun.sipgate.net
    • stun.ekiga.net
    • stun.internetcalls.com
    • stun.noc.ams-ix.net
    • stun.voip.aebc.com
    • stun.voipbuster.com
    • stun.voxgratia.org
    • stun.ipshka.com
    • stun.faktortel.com.au
    • stun.iptel.org
    • stun.voipstunt.com
    • 203.183.172.196:3478
    • s1.taraba.net
    • stun.l.google.com:19302
    • stun1.l.google.com:19302
    • stun2.l.google.com:19302
    • stun3.l.google.com:19302
    • stun4.l.google.com:19302
    • stun.schlund.de
    • stun.rixtelecom.se
    • stun.voiparound.com
    • numb.viagenie.ca
    • stun.stunprotocol.org
    • stun.services.mozilla.com
    • stun.2talk.co.nz
  • Stop the following services:
    • wscsvc
    • MpsSvc
    • WinDefend
  • Start the following service:
    • termservice

It deletes the initially executed copy of itself

NOTES:

This malware sends the following GET request:

/0911us11/{Computer name}_{OS patform}.{BOTID}/{value}/{data/variable}/{BLOCKED}.{BLOCKED}.6.243/

It sends a POST request to send stolen information from the injection.

  SOLUTION

Minimum Scan Engine:

9.80

FIRST VSAPI PATTERN FILE:

12.158.04

FIRST VSAPI PATTERN DATE:

18 Nov 2015

VSAPI OPR PATTERN File:

12.159.00

VSAPI OPR PATTERN Date:

19 Nov 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

Remove malware/grayware files that dropped/downloaded BKDR_DYRE.AM. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • TROJ_UPATRE.YYSQQ

Step 4

Restart in Safe Mode

[ Learn More ]

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.
  • %System%\config\systemprofile\Application Data\{random filename} (for Windows XP and below)
  • %AppDataLocal%\{random filename} (for Windows Vista and above)

Step 6

Restore this modified 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
    • From: LimitBlankPasswordUse = "0"
      To: LimitBlankPasswordUse = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
    • From: fDenyTSConnections = "0"
      To: fDenyTSConnections = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
    • From: fSingleSessionPerUser = "0"
      To: fSingleSessionPerUser = 1

Step 7

Delete the Scheduled Tasks added by this malware/grayware

[ Learn More ]

To delete the added Scheduled Task file:

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

  1. Open the Windows Scheduled Tasks. To do this, click Start>Programs>Accessories>System Tools>Scheduled Tasks.
  2. Double-click on a .JOB file.
  3. Check if the malware path and file name exists in the .JOB file. To do this, check the value in the Run field.
  4. If found, select the .JOB file then press SHIFT+DELETE to permanently delete the file.
  5. Repeat the steps above for the remaining .JOB files.

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

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel of the Task Scheduler Window, click Task Scheduler Library.
  3. In the upper-middle panel, click a Task.
  4. In the lower middle panel, click the Actions tab
  5. Check if the malware path and file name exists in the task. To do this, check the value in the Details column under the Actions tab.
  6. If found, select the task and press DELETE and click Yes to delete the task.
  7. Repeat the steps above for the remaining tasks.

Step 8

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

Step 9

Scan your computer with your Trend Micro product to delete files detected as BKDR_DYRE.AM. 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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Related Blog Entries

    This malware sends the following GET request:

    /0911us11/{Computer name}_{OS patform}.{BOTID}/{value}/{data/variable}/{BLOCKED}.{BLOCKED}.6.243/

    It sends a POST request to send stolen information from the injection.

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