Analysis by: Cris Nowell Pantanilla
ALIASES:

Trojan.Win32.Autoit.emg (Kaspersky), Worm:Win32/Rowmanti.A (Microsoft)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware, Propagates via removable drives

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

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 49,946 bytes
File Type: Other
Memory Resident: Yes
Initial Samples Received Date: 19 Mar 2015
Payload: Compromises system security, Connects to URLs/IPs

Arrival Details

This worm 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:

  • %System Root%\AntiWorm\AntiUsbWorm.zip

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

It creates the following folders:

  • %System Root%\AntiWorm

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

It terminates itself if it finds the following processes in the affected system's memory:

  • combination of the following processes:
    • avp.exe, zonealarm.exe and avguard.exe
    • tcpview.exe, procmon.exe and nod32kui.exe
    • kavmm.exe, procmon.exe and fsbwsys.exe
    • vmacthlp.exe, avp.exe and kavsvc.exe
  • VBoxService.exe
  • VBoxTray.exe
  • guninraik.exe
  • SbieSvc.exe
  • VMwareTray.exe
  • VMwareUser.exe
  • VMwareService.exe
  • VMwareUser.exe
  • FortiTracer.exe
  • vmacthlp.exe
  • vmtoolsd.exe
  • BehaviorDumper.exe
  • FakeHTTPServer.exe
  • FakeServer.exe
  • FakeHTTPServer.exe
  • FakeHTTPServer.exe
  • FakeHTTPServer.exe
  • FakeHTTPServer.exe

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
AntiWormUpdate = "%System Root%\AntiWorm\AntiWormUpdate.lnk"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
AntiUsbWorm = "%System Root%\AntiWorm\AntiUsbWormUpdate.lnk"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
AntiWormUpdate = "%System Root%\AntiWorm\AntiWormUpdate.lnk"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
AntiUsbWorm = "%System Root%\AntiWorm\AntiUsbWormUpdate.lnk"

It drops the following file(s) in the Windows Common Startup folder to enable its automatic execution at every system startup:

  • AntiWormUpdate.lnk
  • AntiUsbWormUpdate.lnk

Other System Modifications

This worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is {user-defined}.)

Propagation

This worm drops the following copy of itself in all physical and removable drives:

  • {drive}:\AntiUsbWorm\AntiUsbWorm.zip

Backdoor Routine

This worm executes the following commands from a remote malicious user:

  • Restart malware
  • Insert script to HTML
  • Update copy
  • Display message box
  • Access a URL specified by remote user
  • Execute command through cmd.exe
  • Download arbitrary files
  • Shutdown
  • Restart
  • Logoff
  • Standby

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}er.{BLOCKED}y.com/update.php
  • http://{BLOCKED}hee.esy.es/update.php
  • http://{BLOCKED}h.fulba.com/update.php
  • {BLOCKED}hee.{BLOCKED}vm.com
  • {BLOCKED}heibh.{BLOCKED}vm.com
  • {BLOCKED}ackw.sytes.net
  • {BLOCKED}ere.{BLOCKED}s.net
  • {BLOCKED}heibh.{BLOCKED}vm.com

Information Theft

This worm gathers the following data:

  • Malware ID
  • Computer name
  • User name
  • Country
  • OS Version
  • OS Architecture (32bit/64bit)
  • Active window title
  • Installed AV application

Other Details

This worm accesses the following URL(s) to get the affected system's location:

  • http://www.geoplugin.net/json.gp

NOTES:

If OS version is Windows7 or windows XP, it will retrieve system information using the following command:

  • %comspec% /c SystemInfo

It terminates itself if system information contains the following strings:

  • Bochs
  • innotek
  • VMware

It will terminate itself if malware filename meets the following conditions:

  • contains artifact string
  • contains sample string
  • does not contain filename length is greater than 35

It will terminate itself if the following folders are present:

  • C:\CWSandbox
  • C:\python26
  • C:\cuckoo
  • C:\virus

It will enumerate process modules. It terminates itself if the following files are found:

  • snxhk.dll
  • tracer.dll
  • SbieDll.dll
  • api_log.dll
  • dir_watch.dll
  • dbghelp.dll
  • monitornet.dll
  • cuckoo
  • SandCastle
  • sandbox
  • tracer.dll

It creates the following shortcut (.LNK) files in removable drives that points to its copy:

  • Downloads
  • Hot
  • Movies
  • My Games
  • My Pictuers
  • My Videos
  • AntiUsbWorm

It also creates shortcut (.LNK) files using folder names as filenames in folders in all drives

The dropped shorcut files are detected as LNK_ROWMANTI.B

It copies all files found in the current malware path to the created “AntiUsbWorm” folder.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.766.10
FIRST VSAPI PATTERN DATE: 19 Mar 2015
VSAPI OPR PATTERN File: 11.767.00
VSAPI OPR PATTERN Date: 20 Mar 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

Remove the malware/grayware file dropped/downloaded by WORM_ROWMANTI.B. (Note: Please skip this step if the threat(s) listed below have already been removed.)

    LNK_ROWMANTI.B

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Restore this modified 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\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "{user-defined}"

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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • AntiWormUpdate = "%System Root%\AntiWorm\AntiWormUpdate.lnk"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • AntiUsbWorm = "%System Root%\AntiWorm\AntiUsbWormUpdate.lnk"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • AntiWormUpdate = "%System Root%\AntiWorm\AntiWormUpdate.lnk"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • AntiUsbWorm = "%System Root%\AntiWorm\AntiUsbWormUpdate.lnk"

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.
{drive}:\AntiUsbWorm\
%System Root%\AntiWorm

Step 7

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