WORM_BRONTOK.BA

August 10, 2013
 Analysis by: Kathleen Notario
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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 modifies the affected system's HOSTS files. This prevents users from accessing certain websites.

  TECHNICAL DETAILS

File Size:

43,072 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Feb 2011

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 files:

  • %System Root%\Baca Bro !!!.txt
  • %System%\s4563\c.bron.tok.txt
  • %System%\s4563\domlist.txt

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It drops the following copies of itself into the affected system:

  • %Application Data%\dv684780x\yesbron.com
  • %Application Data%\jalak-93847815-bali.com
  • %System%\c_38082k.com
  • %System%\s4563\smss.exe
  • %System%\s4563\csrss.exe
  • %System%\s4563\lsass.exe
  • %System%\s4563\m4227.exe
  • %System%\s4563\services.exe
  • %System%\s4563\winlogon.exe
  • %System%\s4563\zh59847884y.exe
  • %Windows%\j6380822.exe
  • %Windows%\o4380827.exe
  • %Windows%\_default38082.pif
  • %Windows%\wi9426\qm4227.exe

It creates the following folders:

  • %Application Data%\dv684780x
  • %System%\s4563
  • %System%\s4563\Spread.Mail.Bro
  • %System%\s4563\Spread.Sent.Bro
  • %Windows%\wi9426

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.. %Windows% is the Windows folder, which is usually C:\Windows.)

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\Policies\
Explorer\run
f1332win = "%Application Data%\dv684780x\yesbron.com"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
f1332win = "%System%\s4563\zh59847884y.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run
A6108r = "%Windows%\_default38082.pif"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
A6108r = "%Windows%\j6380822.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe "%Windows%\o4380827.exe""

(Note: The default value data of the said registry entry is Explorer.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe,%Windows%\j6380822.exe"

(Note: The default value data of the said registry entry is %System%\userinit.exe,.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot
AlternateShell = "c_38082k.com"

(Note: The default value data of the said registry entry is cmd.exe.)

Other System Modifications

This worm adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
AtTaskMaxHours = "48"

It adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\Brontok

It modifies the following registry entries:

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

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

(Note: The default value data of the said registry entry is 0.)

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

(Note: The default value data of the said registry entry is 1.)

HOSTS File Modification

This worm adds the following strings to the Windows HOSTS file:

  • #JowoBot-CrackHost
  • 127.0.0.22 mcafee.com
  • 127.0.0.22 www.mcafee.com
  • 127.0.0.22 mcafee.net
  • 127.0.0.22 www.mcafee.net
  • 127.0.0.22 mcafee.org
  • 127.0.0.22 www.mcafee.org
  • 127.0.0.22 mcafeesecurity.com
  • 127.0.0.22 www.mcafeesecurity.com
  • 127.0.0.22 mcafeesecurity.net
  • 127.0.0.22 www.mcafeesecurity.net
  • 127.0.0.22 mcafeesecurity.org
  • 127.0.0.22 www.mcafeesecurity.org
  • 127.0.0.22 mcafeeb2b.com
  • 127.0.0.22 www.mcafeeb2b.com
  • 127.0.0.22 mcafeeb2b.net
  • 127.0.0.22 www.mcafeeb2b.net
  • 127.0.0.22 mcafeeb2b.org
  • 127.0.0.22 www.mcafeeb2b.org
  • 127.0.0.22 nai.com
  • 127.0.0.22 www.nai.com
  • 127.0.0.22 nai.net
  • 127.0.0.22 www.nai.net
  • 127.0.0.22 nai.org
  • 127.0.0.22 www.nai.org
  • 127.0.0.22 vil.nai.com
  • 127.0.0.22 www.vil.nai.com
  • 127.0.0.22 vil.nai.net
  • 127.0.0.22 www.vil.nai.net
  • 127.0.0.22 vil.nai.org
  • 127.0.0.22 www.vil.nai.org
  • 127.0.0.22 grisoft.com
  • 127.0.0.22 www.grisoft.com
  • 127.0.0.22 grisoft.net
  • 127.0.0.22 www.grisoft.net
  • 127.0.0.22 grisoft.org
  • 127.0.0.22 www.grisoft.org
  • 127.0.0.22 kaspersky-labs.com
  • 127.0.0.22 www.kaspersky-labs.com
  • 127.0.0.22 kaspersky-labs.net
  • 127.0.0.22 www.kaspersky-labs.net
  • 127.0.0.22 kaspersky-labs.org
  • 127.0.0.22 www.kaspersky-labs.org
  • 127.0.0.22 kaspersky.com
  • 127.0.0.22 www.kaspersky.com
  • 127.0.0.22 kaspersky.net
  • 127.0.0.22 www.kaspersky.net
  • 127.0.0.22 kaspersky.org
  • 127.0.0.22 www.kaspersky.org
  • 127.0.0.22 downloads1.kaspersky-labs.com
  • 127.0.0.22 www.downloads1.kaspersky-labs.com
  • 127.0.0.22 downloads1.kaspersky-labs.net
  • 127.0.0.22 www.downloads1.kaspersky-labs.net
  • 127.0.0.22 downloads1.kaspersky-labs.org
  • 127.0.0.22 www.downloads1.kaspersky-labs.org
  • 127.0.0.22 downloads2.kaspersky-labs.com
  • 127.0.0.22 www.downloads2.kaspersky-labs.com
  • 127.0.0.22 downloads2.kaspersky-labs.net
  • 127.0.0.22 www.downloads2.kaspersky-labs.net
  • 127.0.0.22 downloads2.kaspersky-labs.org
  • 127.0.0.22 www.downloads2.kaspersky-labs.org
  • 127.0.0.22 downloads3.kaspersky-labs.com
  • 127.0.0.22 www.downloads3.kaspersky-labs.com
  • 127.0.0.22 downloads3.kaspersky-labs.net
  • 127.0.0.22 www.downloads3.kaspersky-labs.net
  • 127.0.0.22 downloads3.kaspersky-labs.org
  • 127.0.0.22 www.downloads3.kaspersky-labs.org
  • 127.0.0.22 downloads4.kaspersky-labs.com
  • 127.0.0.22 www.downloads4.kaspersky-labs.com
  • 127.0.0.22 downloads4.kaspersky-labs.net
  • 127.0.0.22 www.downloads4.kaspersky-labs.net
  • 127.0.0.22 downloads4.kaspersky-labs.org
  • 127.0.0.22 www.downloads4.kaspersky-labs.org
  • 127.0.0.22 download.mcafee.com
  • 127.0.0.22 www.download.mcafee.com
  • 127.0.0.22 download.mcafee.net
  • 127.0.0.22 www.download.mcafee.net
  • 127.0.0.22 download.mcafee.org
  • 127.0.0.22 www.download.mcafee.org
  • 127.0.0.22 norton.com
  • 127.0.0.22 www.norton.com
  • 127.0.0.22 norton.net
  • 127.0.0.22 www.norton.net
  • 127.0.0.22 norton.org
  • 127.0.0.22 www.norton.org
  • 127.0.0.22 symantec.com
  • 127.0.0.22 www.symantec.com
  • 127.0.0.22 symantec.net
  • 127.0.0.22 www.symantec.net
  • 127.0.0.22 symantec.org
  • 127.0.0.22 www.symantec.org
  • 127.0.0.22 liveupdate.symantecliveupdate.com
  • 127.0.0.22 www.liveupdate.symantecliveupdate.com
  • 127.0.0.22 liveupdate.symantecliveupdate.net
  • 127.0.0.22 www.liveupdate.symantecliveupdate.net
  • 127.0.0.22 liveupdate.symantecliveupdate.org
  • 127.0.0.22 www.liveupdate.symantecliveupdate.org
  • 127.0.0.22 liveupdate.symantec.com
  • 127.0.0.22 www.liveupdate.symantec.com
  • 127.0.0.22 liveupdate.symantec.net
  • 127.0.0.22 www.liveupdate.symantec.net
  • 127.0.0.22 liveupdate.symantec.org
  • 127.0.0.22 www.liveupdate.symantec.org
  • 127.0.0.22 update.symantec.com
  • 127.0.0.22 www.update.symantec.com
  • 127.0.0.22 update.symantec.net
  • 127.0.0.22 www.update.symantec.net
  • 127.0.0.22 update.symantec.org
  • 127.0.0.22 www.update.symantec.org
  • 127.0.0.22 securityresponse.symantec.com
  • 127.0.0.22 www.securityresponse.symantec.com
  • 127.0.0.22 securityresponse.symantec.net
  • 127.0.0.22 www.securityresponse.symantec.net
  • 127.0.0.22 securityresponse.symantec.org
  • 127.0.0.22 www.securityresponse.symantec.org
  • 127.0.0.22 sarc.com
  • 127.0.0.22 www.sarc.com
  • 127.0.0.22 sarc.net
  • 127.0.0.22 www.sarc.net
  • 127.0.0.22 sarc.org
  • 127.0.0.22 www.sarc.org
  • 127.0.0.22 vaksin.com
  • 127.0.0.22 www.vaksin.com
  • 127.0.0.22 vaksin.net
  • 127.0.0.22 www.vaksin.net
  • 127.0.0.22 vaksin.org
  • 127.0.0.22 www.vaksin.org
  • 127.0.0.22 forum.vaksin.com
  • 127.0.0.22 www.forum.vaksin.com
  • 127.0.0.22 forum.vaksin.net
  • 127.0.0.22 www.forum.vaksin.net
  • 127.0.0.22 forum.vaksin.org
  • 127.0.0.22 www.forum.vaksin.org
  • 127.0.0.22 norman.com
  • 127.0.0.22 www.norman.com
  • 127.0.0.22 norman.net
  • 127.0.0.22 www.norman.net
  • 127.0.0.22 norman.org
  • 127.0.0.22 www.norman.org
  • 127.0.0.22 trendmicro.com
  • 127.0.0.22 www.trendmicro.com
  • 127.0.0.22 trendmicro.net
  • 127.0.0.22 www.trendmicro.net
  • 127.0.0.22 trendmicro.org
  • 127.0.0.22 www.trendmicro.org
  • 127.0.0.22 trendmicro-europe.com
  • 127.0.0.22 www.trendmicro-europe.com
  • 127.0.0.22 trendmicro-europe.net
  • 127.0.0.22 www.trendmicro-europe.net
  • 127.0.0.22 trendmicro-europe.org
  • 127.0.0.22 www.trendmicro-europe.org
  • 127.0.0.22 ae.trendmicro-europe.com
  • 127.0.0.22 www.ae.trendmicro-europe.com
  • 127.0.0.22 ae.trendmicro-europe.net
  • 127.0.0.22 www.ae.trendmicro-europe.net
  • 127.0.0.22 ae.trendmicro-europe.org
  • 127.0.0.22 www.ae.trendmicro-europe.org
  • 127.0.0.22 it.trendmicro-europe.com
  • 127.0.0.22 www.it.trendmicro-europe.com
  • 127.0.0.22 it.trendmicro-europe.net
  • 127.0.0.22 www.it.trendmicro-europe.net
  • 127.0.0.22 it.trendmicro-europe.org
  • 127.0.0.22 www.it.trendmicro-europe.org
  • 127.0.0.22 secunia.com
  • 127.0.0.22 www.secunia.com
  • 127.0.0.22 secunia.net
  • 127.0.0.22 www.secunia.net
  • 127.0.0.22 secunia.org
  • 127.0.0.22 www.secunia.org
  • 127.0.0.22 winantivirus.com
  • 127.0.0.22 www.winantivirus.com
  • 127.0.0.22 winantivirus.net
  • 127.0.0.22 www.winantivirus.net
  • 127.0.0.22 winantivirus.org
  • 127.0.0.22 www.winantivirus.org
  • 127.0.0.22 pandasoftware.com
  • 127.0.0.22 www.pandasoftware.com
  • 127.0.0.22 pandasoftware.net
  • 127.0.0.22 www.pandasoftware.net
  • 127.0.0.22 pandasoftware.org
  • 127.0.0.22 www.pandasoftware.org
  • 127.0.0.22 esafe.com
  • 127.0.0.22 www.esafe.com
  • 127.0.0.22 esafe.net
  • 127.0.0.22 www.esafe.net
  • 127.0.0.22 esafe.org
  • 127.0.0.22 www.esafe.org
  • 127.0.0.22 f-secure.com
  • 127.0.0.22 www.f-secure.com
  • 127.0.0.22 f-secure.net
  • 127.0.0.22 www.f-secure.net
  • 127.0.0.22 f-secure.org
  • 127.0.0.22 www.f-secure.org
  • 127.0.0.22 europe.f-secure.com
  • 127.0.0.22 www.europe.f-secure.com
  • 127.0.0.22 europe.f-secure.net
  • 127.0.0.22 www.europe.f-secure.net
  • 127.0.0.22 europe.f-secure.org
  • 127.0.0.22 www.europe.f-secure.org
  • 127.0.0.22 bhs.com
  • 127.0.0.22 www.bhs.com
  • 127.0.0.22 bhs.net
  • 127.0.0.22 www.bhs.net
  • 127.0.0.22 bhs.org
  • 127.0.0.22 www.bhs.org
  • 127.0.0.22 datafellows.com
  • 127.0.0.22 www.datafellows.com
  • 127.0.0.22 datafellows.net
  • 127.0.0.22 www.datafellows.net
  • 127.0.0.22 datafellows.org
  • 127.0.0.22 www.datafellows.org
  • 127.0.0.22 cheyenne.com
  • 127.0.0.22 www.cheyenne.com
  • 127.0.0.22 cheyenne.net
  • 127.0.0.22 www.cheyenne.net
  • 127.0.0.22 cheyenne.org
  • 127.0.0.22 www.cheyenne.org
  • 127.0.0.22 ontrack.com
  • 127.0.0.22 www.ontrack.com
  • 127.0.0.22 ontrack.net
  • 127.0.0.22 www.ontrack.net
  • 127.0.0.22 ontrack.org
  • 127.0.0.22 www.ontrack.org
  • 127.0.0.22 sands.com
  • 127.0.0.22 www.sands.com
  • 127.0.0.22 sands.net
  • 127.0.0.22 www.sands.net
  • 127.0.0.22 sands.org
  • 127.0.0.22 www.sands.org
  • 127.0.0.22 sophos.com
  • 127.0.0.22 www.sophos.com
  • 127.0.0.22 sophos.net
  • 127.0.0.22 www.sophos.net
  • 127.0.0.22 sophos.org
  • 127.0.0.22 www.sophos.org
  • 127.0.0.22 icubed.com
  • 127.0.0.22 www.icubed.com
  • 127.0.0.22 icubed.net
  • 127.0.0.22 www.icubed.net
  • 127.0.0.22 icubed.org
  • 127.0.0.22 www.icubed.org
  • 127.0.0.22 perantivirus.com
  • 127.0.0.22 www.perantivirus.com
  • 127.0.0.22 perantivirus.net
  • 127.0.0.22 www.perantivirus.net
  • 127.0.0.22 perantivirus.org
  • 127.0.0.22 www.perantivirus.org
  • 127.0.0.22 castlecops.com
  • 127.0.0.22 www.castlecops.com
  • 127.0.0.22 castlecops.net
  • 127.0.0.22 www.castlecops.net
  • 127.0.0.22 castlecops.org
  • 127.0.0.22 www.castlecops.org
  • 127.0.0.22 virustotal.com
  • 127.0.0.22 www.virustotal.com
  • 127.0.0.22 virustotal.net
  • 127.0.0.22 www.virustotal.net
  • 127.0.0.22 virustotal.org
  • 127.0.0.22 www.virustotal.org
  • 127.0.0.22 free-av.com
  • 127.0.0.22 www.free-av.com
  • 127.0.0.22 free-av.net
  • 127.0.0.22 www.free-av.net
  • 127.0.0.22 free-av.org
  • 127.0.0.22 www.free-av.org
  • 127.0.0.22 antivirus.com
  • 127.0.0.22 www.antivirus.com
  • 127.0.0.22 antivirus.net
  • 127.0.0.22 www.antivirus.net
  • 127.0.0.22 antivirus.org
  • 127.0.0.22 www.antivirus.org
  • 127.0.0.22 anti-virus.com
  • 127.0.0.22 www.anti-virus.com
  • 127.0.0.22 anti-virus.net
  • 127.0.0.22 www.anti-virus.net
  • 127.0.0.22 anti-virus.org
  • 127.0.0.22 www.anti-virus.org
  • 127.0.0.22 ca.com
  • 127.0.0.22 www.ca.com
  • 127.0.0.22 ca.net
  • 127.0.0.22 www.ca.net
  • 127.0.0.22 ca.org
  • 127.0.0.22 www.ca.org
  • 127.0.0.22 fajarweb.com
  • 127.0.0.22 www.fajarweb.com
  • 127.0.0.22 fajarweb.net
  • 127.0.0.22 www.fajarweb.net
  • 127.0.0.22 fajarweb.org
  • 127.0.0.22 www.fajarweb.org
  • 127.0.0.22 jasakom.com
  • 127.0.0.22 www.jasakom.com
  • 127.0.0.22 jasakom.net
  • 127.0.0.22 www.jasakom.net
  • 127.0.0.22 jasakom.org
  • 127.0.0.22 www.jasakom.org
  • 127.0.0.22 backup.grisoft.com
  • 127.0.0.22 www.backup.grisoft.com
  • 127.0.0.22 backup.grisoft.net
  • 127.0.0.22 www.backup.grisoft.net
  • 127.0.0.22 backup.grisoft.org
  • 127.0.0.22 www.backup.grisoft.org
  • 127.0.0.22 infokomputer.com
  • 127.0.0.22 www.infokomputer.com
  • 127.0.0.22 infokomputer.net
  • 127.0.0.22 www.infokomputer.net
  • 127.0.0.22 infokomputer.org
  • 127.0.0.22 www.infokomputer.org
  • 127.0.0.22 playboy.com
  • 127.0.0.22 www.playboy.com
  • 127.0.0.22 playboy.net
  • 127.0.0.22 www.playboy.net
  • 127.0.0.22 playboy.org
  • 127.0.0.22 www.playboy.org
  • 127.0.0.22 sex-mission.com
  • 127.0.0.22 www.sex-mission.com
  • 127.0.0.22 sex-mission.net
  • 127.0.0.22 www.sex-mission.net
  • 127.0.0.22 sex-mission.org
  • 127.0.0.22 www.sex-mission.org
  • 127.0.0.22 pornstargals.com
  • 127.0.0.22 www.pornstargals.com
  • 127.0.0.22 pornstargals.net
  • 127.0.0.22 www.pornstargals.net
  • 127.0.0.22 pornstargals.org
  • 127.0.0.22 www.pornstargals.org
  • 127.0.0.22 kaskus.com
  • 127.0.0.22 www.kaskus.com
  • 127.0.0.22 kaskus.net
  • 127.0.0.22 www.kaskus.net
  • 127.0.0.22 kaskus.org
  • 127.0.0.22 www.kaskus.org
  • 127.0.0.22 17tahun.com
  • 127.0.0.22 www.17tahun.com
  • 127.0.0.22 17tahun.net
  • 127.0.0.22 www.17tahun.net
  • 127.0.0.22 17tahun.org
  • 127.0.0.22 www.17tahun.org
  • 127.0.0.22 padinet.com
  • 127.0.0.22 www.padinet.com
  • 127.0.0.22 padinet.net
  • 127.0.0.22 www.padinet.net
  • 127.0.0.22 padinet.org
  • 127.0.0.22 www.padinet.org
  • 127.0.0.22 jeruk.padinet.com
  • 127.0.0.22 www.jeruk.padinet.com
  • 127.0.0.22 jeruk.padinet.net
  • 127.0.0.22 www.jeruk.padinet.net
  • 127.0.0.22 jeruk.padinet.org
  • 127.0.0.22 www.jeruk.padinet.org
  • 127.0.0.22 compactbyte.com
  • 127.0.0.22 www.compactbyte.com
  • 127.0.0.22 compactbyte.net
  • 127.0.0.22 www.compactbyte.net
  • 127.0.0.22 compactbyte.org
  • 127.0.0.22 www.compactbyte.org
  • 127.0.0.22 blog.compactbyte.com
  • 127.0.0.22 www.blog.compactbyte.com
  • 127.0.0.22 blog.compactbyte.net
  • 127.0.0.22 www.blog.compactbyte.net
  • 127.0.0.22 blog.compactbyte.org
  • 127.0.0.22 www.blog.compactbyte.org
  • 127.0.0.22 blogs.compactbyte.com
  • 127.0.0.22 www.blogs.compactbyte.com
  • 127.0.0.22 blogs.compactbyte.net
  • 127.0.0.22 www.blogs.compactbyte.net
  • 127.0.0.22 blogs.compactbyte.org
  • 127.0.0.22 www.blogs.compactbyte.org
  • #JowoBot-VM Community

Other Details

This worm connects to the following possibly malicious URL:

  • http://www.{BLOCKED}free.org/Arts/bddwyrk/inf22.css
  • http://{BLOCKED}ing.com/WS1/cgi/x.cgi?NAVG=Tracker&username=dudxwd

NOTES:

It renames the file %System%\msvbvm60.dll to %System%\msvbvm60.dll.{random number}.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

7.842.05

FIRST VSAPI PATTERN DATE:

17 Feb 2011

VSAPI OPR PATTERN File:

7.843.00

VSAPI OPR PATTERN Date:

18 Feb 2011

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

Identify and delete files detected as WORM_BRONTOK.BA using either the Startup Disk or Recovery Console

[ 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\Policies\Explorer\run
    • f1332win = "%Application Data%\dv684780x\yesbron.com"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • f1332win = "%System%\s4563\zh59847884y.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\run
    • A6108r = "%Windows%\_default38082.pif"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • A6108r = "%Windows%\j6380822.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableRegistryTools = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • AtTaskMaxHours = "48"

Step 4

Delete this registry key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CURRENT_USER\Software
    • Brontok

Step 5

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe "%Windows%\o4380827.exe""
      To: Shell = "Explorer.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = "%System%\userinit.exe,%Windows%\j6380822.exe"
      To: Userinit = "%System%\userinit.exe,"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot
    • From: AlternateShell = "c_38082k.com"
      To: AlternateShell = "cmd.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "0"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = "1"
      To: HideFileExt = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"

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.
  • %Application Data%\dv684780x
  • %System%\s4563
  • %Windows%\wi9426

Step 7

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.
  • %System Root%\Baca Bro !!!.txt

Step 8

Scan your computer with your Trend Micro product to delete files detected as WORM_BRONTOK.BA. 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.

Step 9

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System%\drivers\etc\hosts

NOTES:

To Restore Renamed File:

  1. Go to the directory %System%
  2. Rename the file %System%\msvbvm60.dll.{random number} to %System%\msvbvm60.dll


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