WORM_PUSHBOT.BM

 Analysis by: Anthony Joe Melgarejo

 ALIASES:

Worm:Win32/Pushbot.gen!C (Microsoft), Generic.dx!vez (McAfee), Suspicious.SillyFDC (Symantec), Win32/AutoRun.IRCBot.CX worm (NOD32)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm arrives by connecting affected removable drives to a system. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

44,032 bytes

File Type:

EXE

File Compression:

Unknown

Memory Resident:

Yes

Initial Samples Received Date:

07 Sep 2012

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It 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 worm drops the following copies of itself into the affected system:

  • %Windows%\afd.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Terminal Server\
Install\Software\Microsoft\
Windows\CurrentVersion\Run
Cftmon32 = "afd.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Cftmon32 = "afd.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{645FF040-5081-101B-9F08-00AA002F954E}

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and filename} = "{malware path and filename}:*:Enabled:1"

Propagation

This worm creates the following folders in all removable drives:

  • [DRIVE]:\New
  • [DRIVE]:\New\World

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

;fakeit
[autorun
;$@935u8wjofknlshgi
open=New\World\Order.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files using Windows Explorer
shell\\open\command=New\World\Order.exe
shell\\explore\command=New\World\Order.exe
useautoplay=1

NOTES:

This worm drops the copies of itself in all removable drives as {drive letter}:\New\World\Order.exe.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.378.04

FIRST VSAPI PATTERN DATE:

07 Sep 2012

VSAPI OPR PATTERN File:

9.379.00

VSAPI OPR PATTERN Date:

08 Sep 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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 NT\CurrentVersion\Terminal Server\Install\Software\Microsoft\Windows\CurrentVersion\Run
    • Ctfmon32 = "afd.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Cftmon32 = "afd.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path and filename} = "{malware path and filename}:*:Enabled:1"

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.

  • In HKEY_CLASSES_ROOT\CLSID
    • {645FF040-5081-101B-9F08-00AA002F954E}

Step 5

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. [DRIVE]:\New

Step 6

Search and delete AUTORUN.INF files created by WORM_PUSHBOT.BM that contain these strings

[ Learn More ]
;fakeit
[autorun
;$@935u8wjofknlshgi
open=New\World\Order.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files using Windows Explorer
shell\\open\command=New\World\Order.exe
shell\\explore\command=New\World\Order.exe
useautoplay=1

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_PUSHBOT.BM. 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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