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
July 19, 2000
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 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
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.
This security vulnerability research and the exploit development made
by USSR Labs was based on a previous information supplied by a
researcher of GFI Security, known as Metatron, since it against GFI
policies to create exploits.
To test this vulnerability I telneted to an SMTP server and sent the
following to myself:
MAIL FROM: BILLGATES@MICROSOFT.COM
RCPT TO: MY@EMAIL.COM
Date: Thu,13 Jun 2000 12:33:16 +1111111111111111111111111111111111111111111111111111111111111
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.
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:
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.
Malformed Email Spawner.
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:
Windows Console Version:
Windows Console Version Source:
Microsoft Security Bulletin MS00-045: Frequently Asked Questions,
The vulnerability can be eliminated by a default installation of
either of the following upgrades:
Internet Explorer 5.01 Service Pack 1,
Internet Explorer 5.5 on any system except Windows 2000,
Vendor Url: http://www.microsoft.com
Program Url: http://www.microsoft.com/office/outlook/
Underground Security Systems Research:
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.
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