1450.txt

来自「snort入侵检测规则文件2.4 Snort是众所周知的网络入侵检测工具」· 文本 代码 · 共 80 行

Rule:

--
Sid:

1450

--
Summary:
This event is generated when an attempt is made to send a malformed
request to an SMTP server which may cause a Denial of Service.

--
Impact:
Denial of Service (DoS)

--
Detailed Information:
The SMTP standard command "EXPN" is provided by servers to help find
user e-mail accounts.

A malformed request to certain versions of Vintra MailServer can cause a
DoS against that server.
 
--
Affected Systems:

Vixar MailServer for Windows

--
Attack Scenarios:
The attacker needs to connect to a vulnerable server and issue the
following commands.

>telnet victim.foo.com 25
>helo victim
>mail from:doctor
>rcpt to:evil
>expn *@

--
Ease of Attack:

Simple. No exploit software required.

--
False Positives:

None known.

--
False Negatives:

None known.

--
Corrective Action:

Disable the EXPN command on the SMTP server.

Upgrade to the latest non-affected version of the software

--
Contributors:
Sourcefire Research Team
Brian Caswell <[e-mail]>
Nigel Houghton <[e-mail]>
Extra information from Nawapong Nakjang ([e-mail], [e-mail])

--
Additional References:

NT Bugtraq:
http://marc.theaimsgroup.com/?l=ntbugtraq&m=90222454131610&w=2

Command Reference:
http://www.ntmail.co.uk/kb.htm?q=980

--