14th Apr 2003 [SBWID-6142]
COMMAND
MailMax Buffer Overflow (potential DoS)
SYSTEMS AFFECTED
IMAP4rev1 SmartMax IMAPMax 5 (5.0.10.6 and 5.0.10.7)
PROBLEM
Dennis Rand [http://www.Infowarfare.dk] found following:
MailMax is a scalable e-mail server that supports SMTP, IMAP4 and POP3
protocols. Its TCP/IP GUI allows server administration from any
Internet connected server. The Web Admin module allows you to define
domain administrators so they can maintain their own accounts. It also
provides anti-spamming options.
The problem is a Buffer Overflow in the IMAP4 protocol, within the
IMAP4rev1 SmartMax IMAPMax 5, causing the service to stop responding.
The Vulnerability is a Buffer Overflow in the IMAP4rev1 SmartMax
IMAPMax 5. When a malicious attacker sends a large amount into the
password field, in The login procedure.
The following transcript demonstrates a sample exploitation of the
Vulnerabilities:
----------------------------- [Transcript] -----------------------------
nc 127.0.0.1 143
* OK IMAP4rev1 SmartMax IMAPMax 5 Ready
0000 CAPABILITY
* CAPABILITY IMAP4rev1
0000 OK CAPABILITY completed
0001 LOGIN "[email protected]" "A..[50] ..A"
0001 NO Invalid user name or password.
0001 NO Invalid user name or password.
----------------------------- [/Transcript] -----------------------------
When this attack is used there will pop-up a message box on the server,
with the text "Buffer overrun detected! - Program:
<PATH>\IMAPMax.exe" at this time the service shuts down, and has to
be restarted manually, from the service manager.
DETECTION
=========
IMAP4rev1 SmartMax IMAPMax 5 is vulnerable to the above-described
attacks. Earlier versions may be susceptible as well. To determine if a
specific implementation is vulnerable, experiment by following the
above transcript.
SOLUTION
WORK AROUNDS
============
With this vulnerable version of IMAP, the only workaround is to disable
the IMAP4rev1 SmartMax IMAPMax 5 service, there are no workaround in
the configuration.
SmartMax has released a patched version of IMAPMax.exe version 5.0.10.8
which corrects the problem. It can be downloaded at
ftp://ftp.smartmax.com/updates/MailMax 5.0/Files/
Remember to ensure that the file version is 5.0.10.8 or higher.
Update your MailMax Version 5 to the released version 5.5
VENDOR RESPONSE
===============
Thank you for the buffer overrun security notification in our ImapMax
module for MailMax 5. I'm enclosing an updated IMAPMAX which fixes the
buffer overflow vulnerability? We'll be posting this in our MailMax 5.5
update next week.
Regards,
Eric Weber