Can we get this one added to the database , I’ve been having problems with it , They say its a low risk , I disagree with that it’s very hard to remove because u can remove it but then it comes back… And it is a high security risk for identity theft , So please add this to the definitions…
Discovered: 28 June 2007
Updated: 29 June 2007 7:59:49 AM
Also Known As: W32/Amca-A [Sophos]
Type: Worm
Infection Length: 376,832 bytes
Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP
Once executed, the worm creates the following files:
* %Temp%\NESNELER.EXE
* %System%\PAC.EXE
* %System%\[ORIGINAL FILE NAME]
* %System%\lil11.dll
* %System%\MSWINSCK.OCX
* %System%\scrrntr.dll
* %System%\KMON.OCX
* %System%\KTKBDHK3.DLL
* %System%\ACD.CMD
* %System%\ACD2.CMD
The worm then modifies the following registry entry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon"Shell" = “Explorer.exe [ORIGINAL FILE NAME]”
Next, the worm spreads through network shares protected by weak passwords.
The worm then spreads through removable storage devices by creating the following file and setting the attributes to hidden:
[DRIVE LETTER]\activexdebugger32.exe
The worm also creates the following file so that it executes whenever the removable device is used on another computer:
[DRIVE LETTER]\Autorun.inf
The worm then opens a back door and allows a remote attacker to gain access to the compromised computer.
It may attempt to steal sensitive information from the compromised computer and send it to a remote attacker via email.
It may also attempt to download a file from an FTP site to the following location:
%System%\RNSR.EXE
Note: At the time of writing, the downloaded file was not available.
Recommendations
Symantec Security Response encourages all users and administrators to adhere to the following basic security “best practices”:
* Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
* If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
* Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
* Enforce a password policy. Complex passwords make it difficult to ■■■■■ password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
* Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
* Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
* Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
Writeup By: Asuka Yamamoto
