TSPY_ZBOT.YUYAFX

August 15, 2015
 ALIASES:

PWS:Win32/Bamkro.A (Microsoft); Backdoor.Trojan (Symantec); Trojan-Spy.Win32.Zbot.vtgv (Kaspersky); Worm.Win32.AInfBot.l (v) (Sunbelt); Trojan horse Packed2_c.BZQU (AVG)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size:

682,496 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Aug 2015

Arrival Details

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

  • %User Profile%\Speech\conhost.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It creates the following folders:

  • %User Profile%\Microsoft\Speech

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Update = "%User Profile%\Speech\conhost.exe"

Other System Modifications

This spyware deletes the following files:

  • %System%\wuaumgr.exe
  • %User Profile%\Network\svchost.exe
  • %User Profile%\Microsoft\svchost.exe
  • %User Profile%\Microsoft\conhost.exe
  • %System Root%\cer.dat

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Share

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows\CurrentVersion\
Run

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Share
del = "%System Root%\cer.dat"

HKEY_CURRENT_USER\Software\Microsoft\
Share
path = "%User Profile%\Speech\conhost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Share
ver = "138"

HKEY_CURRENT_USER\Software\Microsoft\
Share
scrpt = "{random values}"

Dropping Routine

This spyware drops the following files:

  • %Windows%\system32111.dat
  • %System%\drivers\npf.sys

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

Other Details

This spyware connects to the following possibly malicious URL:

  • http://{BLOCKED}m19.ml
  • http://www.{BLOCKED}myip.org/n09230945.asp
  • http://www.{BLOCKED}myip.org/simple
  • http://{BLOCKED}m19.ml/plugin/np.dat?v=120109
  • http://www.{BLOCKED}myip.org/plugin/np.dat?v=155890
  • {BLOCKED}0.1
  • {BLOCKED}.100.116
  • {BLOCKED}.101.116

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

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

Restart in Safe Mode

[ Learn More ]

Step 3

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\Microsoft
    • Share
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion
    • Run

Step 4

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
    • Update = "%User Profile%\Speech\conhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Share
    • del = "%System Root%\cer.dat"
  • In HKEY_CURRENT_USER\Software\Microsoft\Share
    • path = "%User Profile%\Speech\conhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Share
    • ver = "138"
  • In HKEY_CURRENT_USER\Software\Microsoft\Share
    • scrpt = "{random values}"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %Windows%\system32111.dat
  • %System%\drivers\npf.sys

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\Microsoft\Speech

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.YUYAFX. 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 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System%\wuaumgr.exe
  • %User Profile%\Network\svchost.exe
  • %User Profile%\Microsoft\svchost.exe
  • %User Profile%\Microsoft\conhost.exe
  • %System Root%\cer.dat


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