Symantec Security Response - Backdoor.Semes © 1995-2003 Symantec Corporation. All rights reserved. Legal Notices Privacy Policy Backdoor.Semes Discovered on: September 25, 2003 Last Updated on: September 26, 2003 02:13:15 PM Backdoor.Semes is a Trojan Horse that installs itself in memory and attempts to send confidential information to the Trojan's creator. It also sets the start page of Internet Explorer to a hard-coded URL. Backdoor.Semes is written in Microsoft Visual C++ and is UPX-packed. Type: Trojan Horse Infection Length: 18,167 bytes, 36,864 bytes Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows XP Virus Definitions (Intelligent Updater) * September 26, 2003 Virus Definitions (LiveUpdate™) ** October 01, 2003 *Intelligent Updater definitions are released daily, but require manual download and installation. Click here to download manually. **LiveUpdate virus definitions are usually released every Wednesday. Click here for instructions on using LiveUpdate. Wild: Number of infections: 0 - 49 Number of sites: 0 - 2 Geographical distribution: Low Threat containment: Easy Removal: Easy Threat Metrics Wild: LowDamage: LowDistribution: Low When Backdoor.Semes runs, it does the following: Copies itself to %Windir%\Sendmess.exe. Drops the files %Windir%\Qq32.ini and %System%\Qqmess.dll. Adds the value: "QQ" = %Windir%\sendmess.exe to the registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run so that the Trojan runs when you start Windows. Changes the Internet Explorer home page by adding the value: "Start Page" = "http:/ /www.qq886.com" to the registry key: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer\Main 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. 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. 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. The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines. Update the virus definitions. Do one of the following: Windows 95/98/Me: Restart the computer in Safe mode. Windows NT/2000/XP: End the Trojan process. Run a full system scan and delete all the files detected as Backdoor.Semes (or similar variants). Reverse the changes that the Trojan made to the registry. Reset the Internet Explorer home page. For details on each of these steps, read the following instructions. 1. Updating the virus definitions Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions: Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate). Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater). The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions. 2. Restarting the computer in Safe mode or ending the Trojan process Windows 95/98/Me Restart the computer in Safe mode. All the Windows 32-bit operating systems, except for Windows NT, can be restarted in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Windows NT/2000/XP To end the Trojan process: Press Ctrl+Alt+Delete once. Click Task Manager. Click the Processes tab. Double-click the Image Name column header to alphabetically sort the processes. Scroll through the list and look for Sendmess.exe. If you find the file, click it, and then click End Process. Exit the Task Manager. 3. Scanning for and deleting the infected files Start your Symantec antivirus program and make sure that it is configured to scan all the files. For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files." For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files." Run a full system scan. If any files are detected as infected with Backdoor.Semes, click Delete. 4. Reversing the changes made to the registry CAUTION: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions. Click Start, and then click Run. (The Run dialog box appears.) Type regedit, and then click OK. (The Registry Editor opens.) Navigate to the key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run In the right pane, delete the value: "QQ" = %Windir%\sendmess.exe Exit the Registry Editor. 5. Resetting the Internet Explorer home page Start Microsoft Internet Explorer. Connect to the Internet and go to the page that you want to set as your home page. Click Tools, and then click Internet Options. In the Home page section of the General tab, click Use Current, and then click OK. Write-up by: Scott Gettis