WORM_IRCBOT.WPHT

 Analysis by: Rheniel Rhay Ramos

 ALIASES:

RDN/Sdbot.worm!cc (McAfee); Worm:Win32/Phorpiex.B (Microsoft); W32.IRCBot(Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Worm arrives via removable drives. 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 bypasses the Windows firewall. This allows the malware to perform its intended routine without being detected by an installed firewall.

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:

62,464 bytes

File Type:

EXE

Initial Samples Received Date:

25 Mar 2013

Arrival Details

This Worm arrives via removable drives.

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 and executes them:

  • %User Profile%\P-7-78-8964-9648-3874\wincrs.exe

(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.)

It creates the following folders:

  • %User Profile%\P-7-78-8964-9648-3874

(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.)

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
Microsoft Windows System = "%User Profile%\P-7-78-8964-9648-3874\wincrs.exe"

Other System Modifications

This Worm modifies the following registry entries to disable the Windows Firewall settings:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List\%User Profile%\P-7-78-8964-9648-3874
wincrs.exe = "%User Profile%\P-7-78-8964-9648-3874\wincrs.exe:*:Enabled:Microsoft Windows System"

Propagation

This Worm creates the following folders in all removable drives:

  • {removable drive letter}:\69482745

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

  • {removable drive letter}:\69482745\_TOOLS.exe
  • {removable drive letter}:\wincsa.exe

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

Dropping Routine

This Worm drops the following files:

  • {removable drive letter}:\_TOOLS.lnk

Other Details

This Worm connects to the following possibly malicious URL:

  • {BLOCKED}x.{BLOCKED}cnum.net

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.560.04

FIRST VSAPI PATTERN DATE:

28 Jul 2017

VSAPI OPR PATTERN File:

13.561.00

VSAPI OPR PATTERN Date:

29 Jul 2017

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Terminate a malware/grayware process

[ Learn More ]

*Note: If the detected process is not displayed in theWindows Task Manager, continue doing the next steps.

    • %User Profile%\P-7-78-8964-9648-3874\wincrs.exe

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\SYSTEM\ControlSet001\services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\%User Profile%\P-7-78-8964-9648-3874
    • wincrs.exe = "%User Profile%\P-7-78-8964-9648-3874\wincrs.exe:*:Enabled:Microsoft Windows System"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Microsoft Windows System = "%User Profile%\P-7-78-8964-9648-3874\wincrs.exe"

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.
  • %User Profile%\P-7-78-8964-9648-3874
  • {removable drive letter}:\69482745

Step 6

Search and delete this file

[ Learn More ]
There may be some 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.
  • {removable drive letter}:\_TOOLS.lnk

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_IRCBOT.WPHT. 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.


Did this description help? Tell us how we did.