ALIASES:

PWS-Zbot.gen.vh (McAfee); HEUR:Trojan.Win32.Generic (Kaspersky); Mal/Wonton-S (Sophos); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows

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

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan Spy 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: 1,703,552 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Feb 2020

Arrival Details

This Trojan Spy 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 Trojan Spy adds the following processes:

  • %System%\svchost.exe --HiddenServiceDir "%Application Data%\tor\hidden_service" --HiddenServicePort "55080 127.0.0.1:55080"
  • %System%\svchost.exe (null)
  • %System%\svchost.exe ext "{malware file path and name}"
  • "%User Temp%\cgminer.exe" -o http://{BLOCKED}0.1:64790/btc/ -u user -p UB97ad2 -w 128 -I d -k poclbm --api-listen
  • "%Application Data%\Exylni\qilyc.exe"
  • %System%\svchost.exe ext "%Application Data%\Exylni\qilyc.exe"

It creates the following folders:

  • %Application Data%\Ruox
  • %AppDataLocal%\Microsoft\Windows Mail
  • %Application Data%\Exylni
  • %AppDataLocal%\Microsoft\Windows Mail\Local Folders\Sent Items
  • %Application Data%\tor\hidden_service
  • %Application Data%\microsoft\IdentityCRL
  • %Application Data%\tor
  • %User Temp%\ppcrlui_3144_2.ui
  • %User Profile%\Contacts
  • %Application Data%\microsoft\IdentityCRL\temp

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{1D9B2D00-7A05-5CE3-483D-77D517F0497E} = "%Application Data%\Exylni\qilyc.exe"

Other System Modifications

This Trojan Spy modifies the following file(s):

  • %Application Data%\Ruox\ifru.foa
  • %AppDataLocal%\Microsoft\Windows Mail\edb.chk
  • %AppDataLocal%\Microsoft\Windows Mail\WindowsMail.MSMessageStore

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It deletes the following files:

  • %AppDataLocal%\Microsoft\Windows Mail\edbtmp.log
  • {malware file path and name}

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Ulxo
Avycasyp = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail\Mail
Welcome Message = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail\Junk Mail\Safe Senders List
Version = "327680"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail\Junk Mail\Block Senders List
Version = "327680"

HKEY_CURRENT_USER\Software\Microsoft\
IdentityCRL\Dynamic Salt
Value = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
IdentityCRL\Dynamic Salt
Size = "330"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail
SpoolerDlgPos = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail
SpoolerTack = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail\Mail
Default_CodePage = "28591"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail
Compact Check Count = "2"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail
LastRun = "\xfd!\x81\x9d0\xd5\x01"

HKEY_CURRENT_USER\Software\Microsoft\
Windows Mail
Running = "0"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run\
internat.exe

Dropping Routine

This Trojan Spy drops the following files:

  • %Application Data%\Exylni\qilyc.exe
  • %AppDataLocal%\Microsoft\Windows Mail\edb.chk
  • %AppDataLocal%\Microsoft\Windows Mail\WindowsMail.MSMessageStore
  • %Application Data%\tor\hidden_service\hostname.tmp
  • %User Temp%\cgminer.exe
  • %User Temp%\pthreadGC2.dll
  • %Application Data%\Ruox\ifru.foa
  • %Application Data%\tor\state.tmp
  • %User Temp%\ppcrlui_3144_2
  • %Application Data%\tor\lock
  • %AppDataLocal%\Microsoft\Windows Mail\Local Folders\Inbox\41B45615-00000001.eml
  • %Application Data%\tor\hidden_service\private_key.tmp
  • %Application Data%\tor\cached-certs.tmp
  • %AppDataLocal%\Microsoft\Windows Mail\Local Folders\Inbox\41B45615-00000001.eml:OECustomProperty
  • %User Temp%\libcurl-4.dll
  • %User Temp%\poclbm120222.cl
  • %Application Data%\Ruox\ifru.tmp
  • %Application Data%\tor\cached-consensus.tmp
  • %User Temp%\libpdcurses.dll

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other Details

This Trojan Spy connects to the following possibly malicious URL:

  • http://checkip.{BLOCKED}s.org
  • {BLOCKED}21.38
  • {BLOCKED}.244.244
  • {BLOCKED}40.126
  • {BLOCKED}.203.232

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.850

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Identify and terminate files detected as TrojanSpy.Win32.ZBOT.CDI

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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
    • {1D9B2D00-7A05-5CE3-483D-77D517F0497E} = "%Application Data%\Exylni\qilyc.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Ulxo
    • Avycasyp = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail\Mail
    • Welcome Message = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail\Junk Mail\Safe Senders List
    • Version = "327680"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail\Junk Mail\Block Senders List
    • Version = "327680"
  • In HKEY_CURRENT_USER\Software\Microsoft\IdentityCRL\Dynamic Salt
    • Value = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\IdentityCRL\Dynamic Salt
    • Size = "330"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail
    • SpoolerDlgPos = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail
    • SpoolerTack = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail\Mail
    • Default_CodePage = "28591"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail
    • Compact Check Count = "2"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail
    • LastRun = "\xfd!\x81\x9d0\xd5\x01"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Mail
    • Running = "0"

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.
  • %Application Data%\Exylni\qilyc.exe
  • %AppDataLocal%\Microsoft\Windows Mail\edb.chk
  • %AppDataLocal%\Microsoft\Windows Mail\WindowsMail.MSMessageStore
  • %Application Data%\tor\hidden_service\hostname.tmp
  • %User Temp%\cgminer.exe
  • %User Temp%\pthreadGC2.dll
  • %Application Data%\Ruox\ifru.foa
  • %Application Data%\tor\state.tmp
  • %User Temp%\ppcrlui_3144_2
  • %Application Data%\tor\lock
  • %AppDataLocal%\Microsoft\Windows Mail\Local Folders\Inbox\41B45615-00000001.eml
  • %Application Data%\tor\hidden_service\private_key.tmp
  • %Application Data%\tor\cached-certs.tmp
  • %AppDataLocal%\Microsoft\Windows Mail\Local Folders\Inbox\41B45615-00000001.eml:OECustomProperty
  • %User Temp%\libcurl-4.dll
  • %User Temp%\poclbm120222.cl
  • %Application Data%\Ruox\ifru.tmp
  • %Application Data%\tor\cached-consensus.tmp
  • %User Temp%\libpdcurses.dll

Step 6

Search and delete these folders

[ 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.
  • %Application Data%\Ruox
  • %AppDataLocal%\Microsoft\Windows Mail
  • %Application Data%\Exylni
  • %AppDataLocal%\Microsoft\Windows Mail\Local Folders\Sent Items
  • %Application Data%\tor\hidden_service
  • %Application Data%\microsoft\IdentityCRL
  • %Application Data%\tor
  • %User Temp%\ppcrlui_3144_2.ui
  • %User Profile%\Contacts
  • %Application Data%\microsoft\IdentityCRL\temp

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TrojanSpy.Win32.ZBOT.CDI. 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 deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %Application Data%\Ruox\ifru.foa
    • %AppDataLocal%\Microsoft\Windows Mail\edb.chk
    • %AppDataLocal%\Microsoft\Windows Mail\WindowsMail.MSMessageStore

Step 9

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.

  • %AppDataLocal%\Microsoft\Windows Mail\edbtmp.log
  • {malware file path and name}

Step 10

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • internat.exe


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