Ransom_CERBER.BSED

May 02, 2017
 ALIASES:

RDN/Generic.grp (McAfee); Trojan.Gen.2 (Symantec); Trojan.Win32.Reconyc.hwkz (Kaspersky); Troj/Skeeyah-DO (Sophos); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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:

1,006,395 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 May 2017

Arrival Details

This Trojan 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 creates the following folders:

  • %System Root%\Documents and Settings\Wilbert
  • %User Profile%\m0h9o
  • %User Profile%\Application Data\m0h9o
  • %User Profile%\Application Data\audioplug
  • %Program Files%\audioplug
  • %User Profile%\audioplug\Logs
  • %User Profile%\audioplug\Files
  • %User Profile%\audioplug\Guard
  • %User Profile%\audioplug\Screenshots
  • %User Profile%\Screenshots\04-06-2017

(Note: %System Root% is the Windows root folder, where it usually is C:\ 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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
Client Monitor = "cmd /c start Client Monitor %Program Files%\audioplug\audioplug.exe "

Other System Modifications

This Trojan deletes the following files:

  • %User Profile%\m0h9o\by3jo.exe:Zone.Identifier
  • %Program Files%\audioplug\audioplug.exe:Zone.Identifier

(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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

It adds the following registry entries:

HKEY_CURRENT_USER\Software
pX1nHAOnatpDtqWCCZTzEw== = "3LhoTGHgGUXig+LrlxZGgIXHhmB83MYfOORbnDj/Gx0="

HKEY_CURRENT_USER\Software
ICaOz0bm6DOfffm5mn6Zjw== = "IaLHsmYZbxur9V0oUyhm3w=="

HKEY_CURRENT_USER\Software
PTH = "%Program Files%\audioplug\audioplug.exe"

HKEY_CURRENT_USER\Software
MTX = "c8d981ea9e8276ea6d0dd65a1468b53b8146dfe0"

HKEY_CURRENT_USER\Software
PRC = "1644"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "explorer.exe,%System%\clientmonitor.exe "

HKEY_CURRENT_USER\Software
bNFd2IozPC5O6KUAU4Cgwg== = "z/kL/tMGx4o5wsDlXPOsjiz6sLP8wKsJkjnq1yoQya0="

HKEY_CURRENT_USER\Software
ICaOz0bm6DOfffm5mn6Zjw== = "dPq8qyCwNmwyhRFLlRL9zw=="

HKEY_CURRENT_USER\Software
4oLNcheqmBwkegc9HJ/wAQ== = "LTbGxsRc805/bLvYlgFUTw=="

HKEY_CURRENT_USER\Software
cvuTc2XTWOeAiLRiwlyLIU4p/b6SUNGeAAGo3MBCKuM= = "3ZzoYm5+vqQZpuDElRTutw=="

HKEY_CURRENT_USER\Software
1fzfLJmEZ+f2ebWDaTvNVN2c6GJufr6kGabgxJUU7rc= = "3ZzoYm5+vqQZpuDElRTutw=="

HKEY_CURRENT_USER\Software
xYEtkf/4Uoc6j5zzXqgbFQ== = "{random characters}"

Dropping Routine

This Trojan drops the following files:

  • __tmp_rar_sfx_access_check_34375
  • file.exe
  • 1e5zp.vbs
  • __tmp_rar_sfx_access_check_45500
  • by3jo.exe
  • x
  • %User Profile%\Guard\1
  • %User Profile%\04-06-2017\4.20 PM
  • %User Temp%\1285
  • %Program Files%\audioplug\audioplug.exe
  • %Program Files%\audioplug\audioplug.exe.config
  • %System%\clientmonitor.exe
  • %System%\clientmonitor.exe.config

(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.. %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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}0.15.71
  • {BLOCKED}.188.176

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.8

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • Client Monitor = "cmd /c start Client Monitor %Program Files%\audioplug\audioplug.exe "
  • In HKEY_CURRENT_USER\Software
    • pX1nHAOnatpDtqWCCZTzEw== = "3LhoTGHgGUXig+LrlxZGgIXHhmB83MYfOORbnDj/Gx0="
  • In HKEY_CURRENT_USER\Software
    • ICaOz0bm6DOfffm5mn6Zjw== = "IaLHsmYZbxur9V0oUyhm3w=="
  • In HKEY_CURRENT_USER\Software
    • PTH = "%Program Files%\audioplug\audioplug.exe"
  • In HKEY_CURRENT_USER\Software
    • MTX = "c8d981ea9e8276ea6d0dd65a1468b53b8146dfe0"
  • In HKEY_CURRENT_USER\Software
    • PRC = "1644"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • shell = "explorer.exe,%System%\clientmonitor.exe "
  • In HKEY_CURRENT_USER\Software
    • bNFd2IozPC5O6KUAU4Cgwg== = "z/kL/tMGx4o5wsDlXPOsjiz6sLP8wKsJkjnq1yoQya0="
  • In HKEY_CURRENT_USER\Software
    • ICaOz0bm6DOfffm5mn6Zjw== = "dPq8qyCwNmwyhRFLlRL9zw=="
  • In HKEY_CURRENT_USER\Software
    • 4oLNcheqmBwkegc9HJ/wAQ== = "LTbGxsRc805/bLvYlgFUTw=="
  • In HKEY_CURRENT_USER\Software
    • cvuTc2XTWOeAiLRiwlyLIU4p/b6SUNGeAAGo3MBCKuM= = "3ZzoYm5+vqQZpuDElRTutw=="
  • In HKEY_CURRENT_USER\Software
    • 1fzfLJmEZ+f2ebWDaTvNVN2c6GJufr6kGabgxJUU7rc= = "3ZzoYm5+vqQZpuDElRTutw=="
  • In HKEY_CURRENT_USER\Software
    • xYEtkf/4Uoc6j5zzXqgbFQ== = "{random characters}"

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.
  • __tmp_rar_sfx_access_check_34375
  • file.exe
  • 1e5zp.vbs
  • __tmp_rar_sfx_access_check_45500
  • by3jo.exe
  • x
  • %User Profile%\Guard\1
  • %User Profile%\04-06-2017\4.20 PM
  • %User Temp%\1285
  • %Program Files%\audioplug\audioplug.exe
  • %Program Files%\audioplug\audioplug.exe.config
  • %System%\clientmonitor.exe
  • %System%\clientmonitor.exe.config

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.
  • %System Root%\Documents and Settings\Wilbert
  • %User Profile%\m0h9o
  • %User Profile%\Application Data\m0h9o
  • %User Profile%\Application Data\audioplug
  • %Program Files%\audioplug
  • %User Profile%\audioplug\Logs
  • %User Profile%\audioplug\Files
  • %User Profile%\audioplug\Guard
  • %User Profile%\audioplug\Screenshots
  • %User Profile%\Screenshots\04-06-2017

Step 7

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

  • %User Profile%\m0h9o\by3jo.exe:Zone.Identifier
  • %Program Files%\audioplug\audioplug.exe:Zone.Identifier


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