Re: Exchange SMTP Hole?

From: Gerald Eisenhaur (GEisenhaur_at_Eisenhaur.com)
Date: 11/11/03

  • Next message: Tom Burns: "RE: Exchange SMTP Hole?" 
    Date: Tue, 11 Nov 2003 11:13:57 -0500
To: Tom Burns <tburns@torcausa.com>

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    Hello Tom,

    What your explaining sounds like a SMTP AUTH attack.

    By default Exchange allows relaying for authorized users. So spammers
    have started to brute force logins to relay spam.

    Here are some articles that might help a bit
    http://www.winnetmag.com/MicrosoftExchangeOutlook/Article/ArticleID/40507/MicrosoftExchangeOutlook_40507.html
    http://www.vamsoft.com/orf/authattack.asp

    - --Gerry

    Tom Burns wrote:
    | Good morning all,
    |
    | I have an exchange server that's been running for quite some time (over
    | a year) and had it locked down to prevent relay (spam). It is patched
    | all the way up to 3a.
    |
    | I checked my queues yesterday and got slammed by spam relaying.
    |
    | Is there a security hole that MS does not know about yet in SMTP?????
    |
    | The only way I resolved this was to block connection from 219.x.x.x,
    | 218.x.x.x, 211.x.x.x, etc.
    |
    | This server has been testing aginst ORDB.ORG and shown to NOT be an open
    | relay.
    |
    | If anyone has any suggestions, please let me know.
    |
    |
    | Thomas A. Burns
    | System Administrator
    | Torca Products Inc.
    | Auburn Hills, MI 48326
    | 248-373-8300 x186
    |
    |
    -
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    Don't miss RSA Conference 2004! Choose from over 200 class sessions and
    see demos from more than 250 industry vendors. If your job touches
    security, you need to be here. Learn more or register at
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  • Next message: Tom Burns: "RE: Exchange SMTP Hole?"

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