Trojan.Tannick

1. Creates the empty file xtempx.xxx in the %system% folder
   
   Note: %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
   
   
2. Copies itself to either the %system%\X3YY folder, or the "Microsoft\X3YY" subfolder of the folder given in the following registry entry:
   
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
   Explorer\Shell Folders\AppData
   
   The file name is <8 random characters>.exe.
   
   
3. Adds the value
   
   "x3yy" = "<path to Trojan>"
   
   to the following registry key
   
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
   
   so that the Trojan runs when the computer starts.
   
   
4. Creates the mutex "huevupdcheck2_32_10248" so that only one instance of the Trojan runs at one time.
   
   
5. Attempts to read configuration information from its own body.
   This information includes the following:
   • Two URLS from which the Trojan will attempt to download files
   • An FTP site to which the Trojan attempts to send stolen information
   • A user name and password that the Trojan uses to log in to the remote FTP server
     
     The sample received does not contain these configurations, and the Trojan's download and FTP functions fail.
     
     
6. Attempts to download and execute a file from one of the URLs in step 5.
   This fails because of the missing configuration information that is mentioned in step 5.
   
   
7. Modifies the Internet Explorer startup page to "about:blank".
   
   
8. Attempts to terminate the following processes:
   • ZONEALARM.EXE
   • WFINDV32.EXE
   • WEBSCANX.EXE
   • VSSTAT.EXE
   • VSHWIN32.EXE
   • VSECOMR.EXE
   • VSCAN40.EXE
   • VETTRAY.EXE
   • VET95.EXE
   • TDS2-NT.EXE
   • TDS2-98.EXE
   • TCA.EXE
   • TBSCAN.EXE
   • SWEEP95.EXE
   • SPHINX.EXE
   • SMC.EXE
   • SERV95.EXE
   • SCRSCAN.EXE
   • SCANPM.EXE
   • SCAN95.EXE
   • SCAN32.EXE
   • SAFEWEB.EXE
   • RESCUE.EXE
   • RAV7WIN.EXE
   • RAV7.EXE
   • PERSFW.EXE
   • PCFWALLICON.EXE
   • PCCWIN98.EXE
   • PAVW.EXE
   • PAVSCHED.EXE
   • PAVCL.EXE
   • PADMIN.EXE
   • OUTPOST.EXE
   • NVC95.EXE
   • NUPGRADE.EXE
   • NORMIST.EXE
   • NMAIN.EXE
   • NISUM.EXE
   • NAVWNT.EXE
   • NAVW32.EXE
   • NAVNT.EXE
   • NAVLU32.EXE
   • NAVAPW32.EXE
   • N32SCANW.EXE
   • MPFTRAY.EXE
   • MOOLIVE.EXE
   • LUALL.EXE
   • LOOKOUT.EXE
   • LOCKDOWN2000.EXE
   • JEDI.EXE
   • IOMON98.EXE
   • IFACE.EXE
   • ICSUPPNT.EXE
   • ICSUPP95.EXE
   • ICMON.EXE
   • ICLOADNT.EXE
   • ICLOAD95.EXE
   • IBMAVSP.EXE
   • IBMASN.EXE
   • IAMSERV.EXE
   • IAMAPP.EXE
   • F-STOPW.EXE
   • FRW.EXE
   • FP-WIN.EXE
   • F-PROT95.EXE
   • F-PROT.EXE
   • FPROT.EXE
   • FINDVIRU.EXE
   • F-AGNT95.EXE
   • ESPWATCH.EXE
   • ESAFE.EXE
   • ECENGINE.EXE
   • DVP95_0.EXE
   • DVP95.EXE
   • CLEANER3.EXE
   • CLEANER.EXE
   • CLAW95CF.EXE
   • CLAW95.EXE
   • CFINET32.EXE
   • CFINET.EXE
   • CFIAUDIT.EXE
   • CFIADMIN.EXE
   • BLACKICE.EXE
   • BLACKD.EXE
   • AVWUPD32.EXE
   • AVWIN95.EXE
   • AVSCHED32.EXE
   • AVPUPD.EXE
   • AVPTC32.EXE
   • AVPM.EXE
   • AVPDOS32.EXE
   • AVPCC.EXE
   • AVP32.EXE
   • AVP.EXE
   • AVNT.EXE
   • AVKSERV.EXE
   • AVGCTRL.EXE
   • AVE32.EXE
   • AVCONSOL.EXE
   • AUTODOWN.EXE
   • APVXDWIN.EXE
   • ANTI-TROJAN.EXE
   • ACKWIN32.EXE
   • _AVPM.EXE
   • _AVPCC.EXE
   • _AVP32.EXE
   • NVSVC32.EXE
   • NPROTECT.EXE
   • SAVSCAN.EXE
   • ARMOR2NET.EXE
     
     
9. Creates and loads the file named %system%\unic_32.dll. This file performs the following actions:
   • Creates the empty file %system%\op32mp.log
   • Monitors the Web sites that the user visits, and logs the information in the file named _post.log, which is created in the same folder to which the Trojan was copied in step 2
     
     
10. Registers itself as a service.
    
    
11. Attempts to send the stolen information in step 9 to the attacker by FTP, using the user name and password from step 5. This fails because of the missing configuration information that is mentioned in step 5.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. 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.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.