Sophos

Troj/BagleDl-R

Aliases
  • Email-Worm.Win32.Bagle.bq
Category
Type
What to do
Prevalence low high

Summary

 
Affected operating systems Windows
Characteristics
  • Installs itself in the registry
Protection available since 27 June 2005 01:20:03 (GMT)
Last updated 17 August 2005 14:47:13 (GMT)
Detected by All Sophos products
  • Endpoint Security and Control 9.0
  • Small business solutions 4.0

Action

Please follow the instructions for removing Trojans.

Replace the Hosts file from a backup or edit it in Notepad to remove the changes that the Trojan has made.

Windows NT/2000/XP/2003

In Windows NT/2000/XP/2003 you will also need to edit the following registry entries. The removal of these entries is optional in Windows 95/98/Me. Please read the warning about editing the registry.

At the taskbar, click Start|Run. Type 'Regedit' and press Return. The registry editor opens.

Before you edit the registry, you should make a backup. On the 'Registry' menu, click 'Export Registry File'. In the 'Export range' panel, click 'All', then save your registry as Backup.

Locate the HKEY_LOCAL_MACHINE entry:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run\

and remove any reference to any file you deleted.

Each user has a registry area named HKEY_USERS\[code number indicating user]\. For each user locate the entry:

HKU\[code number]\Software\Microsoft\Windows\
CurrentVersion\Run\

and remove any reference to any file you deleted.

Close the registry editor.

More Information

Troj/BagleDl-R is a downloader Trojan which will download, install and run new software without notification that it is doing so.

Troj/BagleDl-R includes functionality to:

- inject its code into EXPLORER.EXE
- modify the HOSTS file
- disable other software, including anti-virus, firewall and security related applications

Troj/BagleDl-R then attempts to download files from remote websites and run them.

Troj/BagleDl-R may also run MSPAINT.EXE in an attempt to obfuscate itself. Troj/BagleDl-R is a downloader Trojan which will download, install and run new software without notification that it is doing so.

Troj/BagleDl-R includes functionality to:

- inject its code into EXPLORER.EXE
- modify the HOSTS file
- disable other software, including anti-virus, firewall and security related applications

When first run Troj/BagleDl-R copies itself to <System>\winshost.exe and creates the file <System>\wiwshost.exe. The file <System>\wiwshost.exe is also detected by Sophos as Troj/BagleDl-R.

The following registry entries are created to run winshost.exe on startup:

HKCU\Software\Microsoft\Windows\CurrentVersion\Run
winshost.exe
<System>\winshost.exe

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
winshost.exe
<System>\winshost.exe

Registry entries are set as follows:

HKLM\SYSTEM\CurrentControlSet\Services\Alerter
Start
00000004

HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess
Start
00000004

HKLM\SYSTEM\CurrentControlSet\Services\wuauserv
Start
00000004

Troj/BagleDl-R creates a new version of the HOSTS file. The new HOSTS file will typically contain the following:

127.0.0.1 localhost

Troj/BagleDl-R also attempts to modify or delete the following registry entries:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Symantec NetDriver Monitor

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
ccApp

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
NAV CfgWiz

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
SSC_UserPrompt

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
McAfee Guardian

HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
McAfee.InstantUpdate.Monitor

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
APVXDWIN

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
KAV50

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
avg7_cc

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
avg7_emc

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Zone Labs Client

HKLM\SOFTWARE\Symantec

HKLM\SOFTWARE\McAfee

HKLM\SOFTWARE\KasperskyLab

HKLM\SOFTWARE\Agnitum

HKLM\SOFTWARE\Panda Software

HKLM\SOFTWARE\Zone Labs

Troj/BagleDl-R then attempts to download files from remote websites and run them.

Troj/BagleDl-R may also run MSPAINT.EXE in an attempt to obfuscate itself.

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