Analysis by: Cris Nowell Pantanilla
ALIASES:

PWS:Win32/Dyzap.M (Microsoft), Trojan.Win32.Staser.bgpg (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It connects to a website to send and receive information.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 491,008 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 27 Mar 2015

Arrival Details

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

It may be downloaded from the following remote sites:

  • http://{BLOCKED}rhabit.co.uk/wp-content/uploads/2014/09/din-a.pdf

Installation

This spyware drops the following files depending on the platform/operating system of the affected computer:

  • %System%\config\systemprofile\AppData\Local\nw9vbe8cb5.dll - (for Windows XP and lower)
  • %AppDataLocal%\nw9vbe8cb5.dl - (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.)

It drops the following copies of itself depending on the platform/operating system of the affected computer:

  • %Windows%\{random file name}.exe (For Windows XP and below)
  • %AppDataLocal%\{random file name}.exe (For Windows Vista and above)

(Note: %Windows% is the Windows folder, where it usually is C:\Windows 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.)

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

  • Global\zx5fwtw4ep

It injects codes into the following process(es):

  • explorer.exe
  • svchost.exe

Autostart Technique

This spyware registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\googleupdate
ImagePath = "%Windows%\{random file name}.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\googleupdate
DisplayName = "Google Update Service"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\googleupdate
ObjectName = "LocalSystem"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
GoogleUpdate = "%AppDataLocal%\{random file name}.exe" (For Windows Vista and above)

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\googleupdate (For Windows XP and below)

Backdoor Routine

This spyware connects to the following websites to send and receive information:

  • {BLOCKED}.{BLOCKED}.191.212:443
  • {BLOCKED}.{BLOCKED}.40.82:443
  • {BLOCKED}.{BLOCKED}.122.136:4443
  • {BLOCKED}.{BLOCKED}.31.194:443
  • {BLOCKED}.{BLOCKED}.131.94:443
  • {BLOCKED}.{BLOCKED}.78.201:443
  • {BLOCKED}.{BLOCKED}.152.131:443
  • {BLOCKED}.{BLOCKED}.40.44:4443
  • {BLOCKED}.{BLOCKED}.239.151:443
  • {BLOCKED}.{BLOCKED}.239.151:4443
  • {BLOCKED}.{BLOCKED}.190.84:443
  • {BLOCKED}.{BLOCKED}.190.88:443
  • {BLOCKED}.{BLOCKED}.214.203:443
  • {BLOCKED}.{BLOCKED}.243.60:4443
  • {BLOCKED}.{BLOCKED}:4443
  • {BLOCKED}.{BLOCKED}.138.151:4443
  • {BLOCKED}.{BLOCKED}.101.221:4443
  • {BLOCKED}.{BLOCKED}:4443
  • {BLOCKED}.{BLOCKED}.254.183:443
  • {BLOCKED}.{BLOCKED}.241.244:4443
  • {BLOCKED}.{BLOCKED}.96.214:443
  • {BLOCKED}.{BLOCKED}.96.84:443
  • {BLOCKED}.{BLOCKED}.97.215:4443
  • {BLOCKED}.{BLOCKED}.97.216:443
  • {BLOCKED}.{BLOCKED}.97.49:443
  • {BLOCKED}.{BLOCKED}.98.128:443
  • {BLOCKED}.{BLOCKED}.98.232:4443
  • {BLOCKED}.{BLOCKED}.98.248:4443
  • {BLOCKED}.{BLOCKED}.69.144:443
  • {BLOCKED}.{BLOCKED}.69.151:4443
  • {BLOCKED}.{BLOCKED}.69.159:4443
  • {BLOCKED}.{BLOCKED}.69.172:4443
  • {BLOCKED}.{BLOCKED}.175.138:443
  • {BLOCKED}.{BLOCKED}.34.137:443
  • {BLOCKED}.{BLOCKED}.250.93:443
  • {BLOCKED}.{BLOCKED}.151.39:443
  • {BLOCKED}.{BLOCKED}.228.155:443
  • {BLOCKED}.{BLOCKED}.249.207:443
  • {BLOCKED}.{BLOCKED}.109.116:443
  • {BLOCKED}.{BLOCKED}.99.217:443
  • {BLOCKED}.{BLOCKED}.74.70:443
  • {BLOCKED}.{BLOCKED}.52.191:443
  • {BLOCKED}.{BLOCKED}.52.192:443
  • {BLOCKED}.{BLOCKED}.53.142:4443
  • {BLOCKED}.{BLOCKED}.54.100:4443
  • {BLOCKED}.{BLOCKED}.177.142:4443
  • {BLOCKED}.{BLOCKED}.178.46:4443
  • {BLOCKED}.{BLOCKED}.91.230:443
  • {BLOCKED}.{BLOCKED}.195.147:443/account/1
  • {BLOCKED}.{BLOCKED}.195.147:443/contact/1
  • {BLOCKED}.{BLOCKED}.195.147:443/info/1
  • {BLOCKED}.{BLOCKED}.195.147:443/login/1
  • {BLOCKED}.{BLOCKED}.199.30:443
  • {BLOCKED}.{BLOCKED}.88.84:4443
  • {BLOCKED}.{BLOCKED}:4443

Other Details

This spyware 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 deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.520.06
FIRST VSAPI PATTERN DATE: 17 Feb 2015
VSAPI OPR PATTERN File: 11.521.00
VSAPI OPR PATTERN Date: 18 Feb 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

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.

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\googleupdate (For Windows XP and below)

Step 5

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
    • GoogleUpdate = "%AppDataLocal%\{random file name}.exe" (For Windows Vista and above)

Step 6

Search and delete this file

[ 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.
  • %AppDataLocal%\nw9vbe8cb5.dll -  (for Vista and higher)
  • %System%\config\systemprofile\AppData\Local\nw9vbe8cb5.dll - (for Windows XP and lower)

Step 7

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