-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft IE Upgrade Trojan Horse Program August 14, 1998 18:00 GMT Number I-085 ______________________________________________________________________________ PROBLEM: An e-mail message with an attachment claiming to be a software update for Internet Explorer from Microsoft Technical Support actually contains a Trojan Horse program. This Trojaned attachment, if executed, sends out Spam e-mail to several locations on the Internet. PLATFORM: Windows 95/98 and Windows NT. DAMAGE: No physical damage or lost data. Damage to reputation due to Spam mail sent from users machine and clogged e-mail servers. SOLUTION: Do not execute attachments in e-mail messages from unknown sources that are either unsolicited and/or not digitally signed. To remove the Trojan after it has run, delete the Trojaned file, shell32.exe, from the %system root% directory and remove the reference to shell32.exe from the Window's registry key. ______________________________________________________________________________ VULNERABILITY Medium. Several reports have been sent to CIAC of the ASSESSMENT: existence of this Trojan Horse circulating the Internet thus it is in the wild. ______________________________________________________________________________ DESCRIPTION CIAC has received information that an e-mail message is being circulated on the Internet that professes to be from Microsoft technical support. This message, which isn't from Microsoft technical support, claims to be a security update for Microsoft Internet Explorer. The message contains an attachment typically named ie080898.exe, however variations of the file name have been reported. The attachment is actually a Trojan Horse program targeted at Microsoft Windows 95, 98, and NT, which sends Spam e-mail messages to several locations on the Internet. For a more detailed explanation on Spam refer to CIAC Bulletin I-005C at: http://ciac.llnl.gov/ciac/bulletins/i-005c.shtml The message looks something like the following: Subject: FREE! Your upgrade for Microsoft Internet Explorer As user of Microsoft Internet Explorer Microsoft Corporation provide you an upgrade for your Microsoft Internet Explorer. Please run Ie080898.exe to install the upgrade. This file will fix some serious bugs in your Internet Explorer. . . . When the user restarts the computer with the Trojaned program installed an Internet connection is made to multiple remote locations and Spam e-mail is sent. This e-mail Spamming continues until the computer is shutdown. The recipient address is randomly selected from the following list: gerry@tetra.bg administrator@tetra.bg tetranet@tetra.bg root@vt.bitex.com peterc@vt.bitex.com ivanp@vt.bitex.com root@tarnovo.eunet.bg master@tarnovo.eunet.bg webmaster@tarnovo.eunet.bg root@server.vt.bia-bg.com webmaster@mail.vt.bia-bg.com webmaster@tetra.bg Windows 95/98 and Windows NT: When the e-mail attachment is executed it installs shell32.exe into the Windows %system root% directory (usually c:\winnt for Windows NT and c:\windows for Windows 95/98) and adds a reference to that program to the following Window's registry key (hkey_local_machine/software/microsoft/windows/currentversion/run/default). The modification causes the Trojaned shell32.exe to execute each time the machine is restarted. SOLUTIONS: CIAC highly recommends if you receive this e-mail message do not execute the attachment. Turn the message over to your local computer security officer for appropriate handling. There are several clues that this e-mail message is not a legitimate message from Microsoft Corporation. Microsoft has stated they never send program updates by e-mail attachments to their users. Although the e-mail message sounds technically correct, it is poorly written and uses improper grammar. For more information on how to spot e-mail hoaxes, see CIAC's hoax web page at: http://ciac.llnl.gov/ciac/CIACHoaxes.html If the Trojan program was run, you can remove the added files by taking the following steps. ****************************************************************** Warning: "Using Registry Editor incorrectly can cause serious, system wide problems that may require you to reinstall Windows 95/98, or Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk." [Microsoft Corp.] ****************************************************************** Windows 95/98: Reboot the infected computer into DOS mode and delete shell32.exe located in the Window's 95/98 %system root% directory. This step stops the unwanted Spam e-mail from being sent out from the machine. The reference to shell32.exe should be removed from the Window's registry from the Window's registry key (hkey_local_machine/software/microsoft/windows/currentversion/run/default) however this is not absolutely necessary. It is important that when looking for and removing the shell32.exe file you don't mistake this file for shell32.dll. Windows NT Delete shell32.exe located in the Window's NT %system root% directory. This will stop the unwanted Spam e-mail from being sent out from the machine. The reference to shell32.exe should be removed from the Window's NT registry key (hkey_local_machine/software/microsoft/windows/currentversion/run/default) however this is not absolutely necessary. It is important that when looking for and removing the shell32.exe file you don't mistake this file for shell32.dll. As a broader way to address this class of problems, users should always take care when opening attachments sent in e-mail (specially that are either unsolicited and/or not digitally signed). Ie., today it is this e-mail, tomorrow it may be some other person, spoofing some other corporation or government entity. ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft Corp. for the information contained in this bulletin. ______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@llnl.gov For emergencies and off-hour assistance, DOE, DOE contractor sites, and the NIH may contact CIAC 24-hours a day. During off hours (5PM - 8AM PST), call the CIAC voice number 925-422-8193 and leave a message, or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC duty person, and the secondary PIN number, 8550074 is for the CIAC Project Leader. Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ (or http://ciac.llnl.gov -- they're the same machine) Anonymous FTP: ftp.ciac.org (or ciac.llnl.gov -- they're the same machine) Modem access: +1 (925) 423-4753 (28.8K baud) +1 (925) 423-3331 (28.8K baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 3. SPI-NOTES, for discussion of problems and solutions regarding the use of SPI products. Our mailing lists are managed by a public domain software package called Majordomo, which ignores E-mail header subject lines. To subscribe (add yourself) to one of our mailing lists, send the following request as the E-mail message body, substituting ciac-bulletin, spi-announce OR spi-notes for list-name: E-mail to ciac-listproc@llnl.gov or majordomo@tholia.llnl.gov: subscribe list-name e.g., subscribe ciac-bulletin You will receive an acknowledgment email immediately with a confirmation that you will need to mail back to the addresses above, as per the instructions in the email. This is a partial protection to make sure you are really the one who asked to be signed up for the list in question. If you include the word 'help' in the body of an email to the above address, it will also send back an information file on how to subscribe/unsubscribe, get past issues of CIAC bulletins via email, etc. PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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