W32.Chir.B@mm

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Discovered: July 29, 2002
Updated: July 30, 2002 7:47:41 PM
Also Known As: Win32.Chir.B [Computer Associates], W32/Chir-B [Sophos], Runouce [F-Secure], PE_CHIR.B [Trend]
Systems Affected: Windows

W32.Chir.B@mm is a mass-mailing worm and virus that sends itself to email addresses gathered from the compromised computer. It exploits remote vulnerabilities and attempts to infect files.

Antivirus Protection Dates

  • Initial Rapid Release version July 30, 2002
  • Latest Rapid Release version April 23, 2018 revision 018
  • Initial Daily Certified version July 30, 2002
  • Latest Daily Certified version April 22, 2018 revision 033
  • Initial Weekly Certified release date July 31, 2002

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Yana Liu

Discovered: July 29, 2002
Updated: July 30, 2002 7:47:41 PM
Also Known As: Win32.Chir.B [Computer Associates], W32/Chir-B [Sophos], Runouce [F-Secure], PE_CHIR.B [Trend]
Systems Affected: Windows

W32.Chir.B@mm is a mass mailing worm that sends itself to all email addresses in a compromised user's Microsoft Outlook address book. It typically arrives as an email message with the following properties:
From:
(One of the following)

  • [USER NAME]@yahoo.com
  • imissyou@btamail.net.cn
Subject: [USER NAME] is coming!
Attachments: PP.exe

The email message attempts to exploit the following vulnerabilities in order to automatically execute the message attachment:
  • Microsoft Virtual Machine com.ms.activeX.ActiveXComponent Arbitrary Program Execution Vulnerability (BID 1754)
  • Microsoft IE MIME Header Attachment Execution Vulnerability (BID 2524)

Once executed, the worm will copy itself as the following file with the Hidden, System, and Read-Only file attributes set:
C:\WINDOWS\SYSTEM\runouce.exe

It then creates the following registry entry so that it is executed every time Windows starts:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"Runonce" = "C:\WINDOWS\SYSTEM\runouce.exe"

The worm then enumerates network resources and attempts to access and modify files.

The worm utilizes its own SMTP engine through a single static SMTP relay (btamail.net.cn). It gathers email addresses by searching the Windows Address Book and the following file extensions:
  • .adc
  • r.db
  • .doc
  • .xls
On the first of every month upon startup, the worm will attempt to overwrite the first 1,234 bytes of files with the above-referenced extensions.

The worm searches through all local and mapped drives to infect files with the following extensions:
  • .htm
  • .html
  • .exe
  • .scr

It creates the following file which is a MIME encoded version of the virus to infect HTML files:
Readme.eml file

It creates The Readme.eml in the same folder in which the HTML file is located. The HTML file is modified to open Readme.eml when the HTML file is viewed, if JavaScript execution is enabled.

The worm will also attempt to infect PE file by appending itself to the last section of the host file. Executing any infected file will cause the virus to load itself into memory and start its mass-mailing routine.

The worm creates the following mutex so only one instance of the worm is running:
ChineseHacker-2

Writeup By: Yana Liu

Discovered: July 29, 2002
Updated: July 30, 2002 7:47:41 PM
Also Known As: Win32.Chir.B [Computer Associates], W32/Chir-B [Sophos], Runouce [F-Secure], PE_CHIR.B [Trend]
Systems Affected: Windows

You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan . If that does not resolve the problem you can try one of the options available below.



FOR NORTON USERS
If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool


If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .


How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.


FOR BUSINESS USERS
If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.


Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .


How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network



MANUAL REMOVAL
The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product


2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.

Writeup By: Yana Liu