WORM_PUSHBOT.CY

 Analysis by: Nikko Tamana

 ALIASES:

Mal/Buzus-GA (Sophos), W32/Injector.HRV!tr (Fortinet), W32/CeeInject.AE.gen!Eldorado (FProt), Trojan.Win32.Menti (Ikarus), Backdoor.Win32.Bifrose.fyb (Kaspersky), VirTool:Win32/CeeInject.gen!FI (Microsoft), a variant of Win32/Injector.HNC trojan (NOD32)

 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:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via removable drives

This worm arrives via removable drives.

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

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size:

99,328 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Jul 2013

Payload:

Compromises system security

Arrival Details

This worm arrives via removable drives.

Installation

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

  • %User Temp%\lsass.exe

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • jiuhuig

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Firewall = "%User Temp%\lsass.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Firewall = "%User Temp%\lsass.exe"

Propagation

This worm creates the following folders in all removable drives:

  • {Removable Drive}:\ TTHDHGC
  • {Removable Drive}:\ TTHDHGC\DFG-2352-66235-2352322-634621321-6662355

It drops the following copy(ies) of itself in all removable drives:

  • {Removable Drives}:\TTHDHGC\DFG-2352-66235-2352322-634621321-6662355\364855.exe

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:

[autorun]
open=TTHDHGC\DFG-2352-66235-2352322-634621321-6662355\364855.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open\command=TTHDHGC\DFG-2352-66235-2352322-634621321-6662355\364855.exe
shell\open\default=1

Backdoor Routine

This worm connects to any of the following IRC server(s):

  • irc.{BLOCKED}ol.co.cc

It accesses a remote Internet Relay Chat (IRC) server where it receives the following commands from a remote malicious user:

  • Delete itself
  • Kill Specific Processes
  • Establish New IRC Connection
  • Download and Execute Adware
  • Propagate via MSN
  • Propagate via Torrent
  • Update itself

Dropping Routine

This worm sets the attributes of its dropped file(s) to the following:

  • Read Only
  • Hidden
  • System

Information Theft

This worm does not have any information-stealing capability.

Other Details

This worm uses the following credentials when accessing its IRC server:

  • NICK [USA][{OS Version}]{Random Numbers}
  • PASS ciaxx

NOTES:

Where {OS Version} can be any of the following depending on affected machine's OS Version:

  • 2K
  • XP
  • VS
  • W7
  • UNK

It propagates via MSN as one of its backdoor commands using the following file name:

  • google_cache113.tmp

It seeds itself in a torrent software as one of its backdoor commands by creating a .torrent file and executing it. The .torrent file it creates uses the following file name:

  • %User Temp%\torr.torrent

It deletes itself as one of its backdoor commands by creating and executing the following batch file:

  • %User Temp%\removeMe{values}.bat

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.300

VSAPI OPR PATTERN File:

10.137.80

VSAPI OPR PATTERN Date:

06 Jul 2013

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 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
    • Windows Firewall = "%User Temp%\lsass.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Windows Firewall = "%User Temp%\lsass.exe"

Step 4

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.
  • {Removable Drive}:\TTHDHGC

Step 5

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

[ Learn More ]
[autorun]
open=TTHDHGC\DFG-2352-66235-2352322-634621321-6662355\364855.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open\command=TTHDHGC\DFG-2352-66235-2352322-634621321-6662355\364855.exe
shell\open\default=1

Step 6

Search and delete these files

[ Learn More ]
There may be some component files 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.
  • %User Temp%\removeMe{values}.bat
  • %User Temp%\torr.torrent

Step 7

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