SMTP daemon supports EHLO
| smtp-ehlo (323) |  Low Risk |
Description:
SMTP daemons that support Extended HELO (EHLO) can release information that could be useful to an attacker in performing an attack. Attackers have been known to use the EHLO command to determine configuration information on SMTP daemons.
Consequences:
Obtain Information
Remedy:
SMTP as defined in RFC 2821 (see References) requires EHLO. Some SMTP implementations allow you to disable EHLO, but this capability is neither required nor consistent across products.
If you are uncomfortable with the information that the Extended SMTP features can reveal, you may choose to disable EHLO on your mail server (if applicable), or switch to a mail server that allows EHLO to be disabled. Consult your mail server documentation or contact your vendor for information on whether it is possible to modify your mail server configuration to disable EHLO.
References:
- Microsoft Exchange 5.5 Product Documentation: Disabling ESMTP Support.
- Request for Comments: 2821: Simple Mail Transfer Protocol.
- CVE-1999-0531: An SMTP service supports EXPN, VRFY, HELP, ESMTP, and/or EHLO.
Platforms Affected:
- Apple Mac OS
- Compaq Tru64
- Data General DG/UX
- IBM AIX
- IBM OS2
- IETF SMTP
- Linux Kernel
- Microsoft Windows 2000
- Microsoft Windows 2003 Server
- Microsoft Windows 95
- Microsoft Windows 98
- Microsoft Windows 98SE
- Microsoft Windows Me
- Microsoft Windows NT 4.0
- Microsoft Windows Vista
- Microsoft Windows XP
- SCO SCO Unix
- SGI IRIX
- Sun Solaris
- WindRiver BSDOS
- HP-UX
Reported:
Not available
The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall the author/distributor (IBM Internet Security Systems X-Force) be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.
For corrections or additions please email xforce@iss.net