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Worm:Win32/Brontok.AO@mm

First posted on 03 March 2019.
Source: Microsoft

Aliases :

Worm:Win32/Brontok.AO@mm is also known as W32/Rontokbro.gen@MM, Email-Worm.Win32.Brontok.q, W32/Brontok-N, W32.Rontokbro@mm.

Explanation :

Worm:Win32/Brontok.AO@mm is a member of Win32/Brontok - a family of mass-mailing email worms. The worm spreads by sending a copy of itself as an email attachment to email addresses that it gathers from files on the infected computer. It can also copy itself to USB and pen drives. Win32/Brontok can disable antivirus and security software, immediately terminate certain applications, and cause Windows to restart when certain applications run. The worm may also conduct denial of service (DoS) attacks against certain websites. Installation When executed, Worm:Win32/Brontok.AO@mm copies itself to the following locations:

%windir%sembako-cjzjlmi.exe %windir%shellnewbm-xqtlmijc.exe administrator's setting.scr cmd-bro-mlx.exe dxblbm.exe c:documents and settingsadministratorlocal settingsapplication datar7911on.exe c:documents and settingsadministratorlocal settingsapplication datacsrss.exe c:documents and settingsadministratorlocal settingsapplication datainetinfo.exe c:documents and settingsadministratorlocal settingsapplication datalsass.exe c:documents and settingsadministratorlocal settingsapplication dataservices.exe c:documents and settingsadministratorlocal settingsapplication datasmss.exe c:documents and settingsadministratorlocal settingsapplication datasvchost.exe c:documents and settingsadministratorlocal settingsapplication datawinlogon.exe c:documents and settingsadministratorstart menuprogramsstartupempty.pif c:documents and settingsadministrator emplates14004-nendangbro.com
Note: refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the System folder for Windows 2000 and NT is C:WinntSystem32; and for XP, Vista, and 7 is C:WindowsSystem32.
The malware modifies the following registry entries to ensure that its copy executes at each Windows start:

Adds value: "Tok-Cirrhatus-3444"
With data: "c:documents and settingsadministratorlocal settingsapplication datar7911on.exe"
To subkey: HKCUSoftwareMicrosoftwindowscurrentversion
un
Adds value: "Shell"
With data: "explorer.exe "c:windowssembako-cjzjlmi.exe""
To subkey: HKLMSOFTWAREMicrosoftWindows NTCurrentVersionWinlogon
The malware creates the following files on an affected computer:
sistem.sys c:autoexec.bat c:documents and settingsadministratorlocal settingsapplication dataronmesmalware.dat.ini c:documents and settingsadministratorlocal settingsapplication dataronmessmss.ini c:documents and settingsadministratorlocal settingsapplication dataronmeswinlogon.ini Payload Modifies system settings Worm:Win32/Brontok.AO@mm removes the Folder Options item from all Explorer menus and the Control Panel by making the following registry modification:

Adds value: "NoFolderOptions"
With data: "1"
To subkey: HKCUSOFTWAREMicrosoftWindowsCurrentVersionPoliciesExplorer

Note: Removing access to these options may hinder the affected user's ability to detect and remove malware.
This malware description was produced and published using our automated analysis system's examination of file SHA1 b852bac5435441520b0630860bd17cd3aec04f9b.

Last update 03 March 2019

 

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