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Incoming email from one particular sender, with attachments timing out.

DanielBarnes

I have a Sophos UTM sitting in front of a X-Wall SMTP server.
The Sophos has its anti-spam settings turned off, so it is just doing NATTING on port 25 through to the X-Wall.

Emails from (at least) one particular sender, with some PDF attachments are timing out every time.
All other emails (that I am aware of) are come through OK.

Here is the relevant log from the x-wall:

16-08-12 00:07:44 0005: Connection opened by mail-sy3aus01on0102.outbound.protection.outlook.com [104.47.117.102]
16-08-12 00:07:44 0005: > 220 (removed - our mail server)  ESMTP XWall v3.52
16-08-12 00:07:44 0005: < EHLO AUS01-SY3-obe.outbound.protection.outlook.com
16-08-12 00:07:44 0005: > 250-(removed - our mail server)
16-08-12 00:07:45 0005: < MAIL FROM:<removed> SIZE=551655 BODY=7BIT
16-08-12 00:07:46 0005: > 250 2.1.0 originator <removed> ok
16-08-12 00:07:46 0005: < RCPT TO:<removed>
16-08-12 00:07:46 0005: > 250 2.1.5 recipient <removed> ok
16-08-12 00:07:46 0005: < BDAT 532861 LAST
16-08-12 00:10:46 0005: Error: Timeout in reading data [9]
16-08-12 00:10:46 0005: Connection closed with mail-sy3aus01on0102.outbound.protection.outlook.com [104.47.117.102]

so it times out after 3 minutes.

I initially contacted X-Wall support, they are confident it is what is sitting in front of the X-Wall (The Sophos UTM) that is causing the issue.
My gut feeling is the Application Control, but I am unsure where I would check in the logs to find an answer, or see if this is occurring to other emails...

Any help or suggestions would be greatly appreciated.



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  • 0

    Ok, I found the cause (for other peoples reference)

    UTM is misclassifying what I am believe is legit email traffic (since it is from *.protection.outlook.com and I am expecting it and it looks legit to me)
    as "Intrusion protection".


    UTM Intrusion protection log:

    2016:08:16-06:10:39 utm snort[21128]: id="2101" severity="warn" sys="SecureNet" sub="ips" name="Intrusion protection alert" action="drop" reason="SERVER-OTHER Symantec MIME parser updateheader heap buffer overflow attempt" group="500" srcip="104.47.117.98" dstip="<local ip removed>" proto="6" srcport="10629" dstport="25" sid="39380" class="Attempted User Privilege Gain" priority="1" generator="1" msgid="0"

    2016:08:16-06:16:26 utm snort[21128]: id="2101" severity="warn" sys="SecureNet" sub="ips" name="Intrusion protection alert" action="drop" reason="SERVER-OTHER Symantec MIME parser updateheader heap buffer overflow attempt" group="500" srcip="104.47.116.124" dstip="<local ip removed>" proto="6" srcport="17526" dstport="25" sid="39380" class="Attempted User Privilege Gain" priority="1" generator="1" msgid="0"


    2016:08:16-06:16:45 utm snort[21128]: id="2101" severity="warn" sys="SecureNet" sub="ips" name="Intrusion protection alert" action="drop" reason="SERVER-OTHER Symantec MIME parser updateheader heap buffer overflow attempt" group="500" srcip="104.47.117.130" dstip="<local ip removed>" proto="6" srcport="65168" dstport="25" sid="39380" class="Attempted User Privilege Gain" priority="1" generator="1" msgid="0"

    As a work around I have configured an exception for Intrusion Prevention for any SMTP incoming traffic. Not perfect I know, but it is a work around that will get the email I need.

Reply
  • 0

    Ok, I found the cause (for other peoples reference)

    UTM is misclassifying what I am believe is legit email traffic (since it is from *.protection.outlook.com and I am expecting it and it looks legit to me)
    as "Intrusion protection".


    UTM Intrusion protection log:

    2016:08:16-06:10:39 utm snort[21128]: id="2101" severity="warn" sys="SecureNet" sub="ips" name="Intrusion protection alert" action="drop" reason="SERVER-OTHER Symantec MIME parser updateheader heap buffer overflow attempt" group="500" srcip="104.47.117.98" dstip="<local ip removed>" proto="6" srcport="10629" dstport="25" sid="39380" class="Attempted User Privilege Gain" priority="1" generator="1" msgid="0"

    2016:08:16-06:16:26 utm snort[21128]: id="2101" severity="warn" sys="SecureNet" sub="ips" name="Intrusion protection alert" action="drop" reason="SERVER-OTHER Symantec MIME parser updateheader heap buffer overflow attempt" group="500" srcip="104.47.116.124" dstip="<local ip removed>" proto="6" srcport="17526" dstport="25" sid="39380" class="Attempted User Privilege Gain" priority="1" generator="1" msgid="0"


    2016:08:16-06:16:45 utm snort[21128]: id="2101" severity="warn" sys="SecureNet" sub="ips" name="Intrusion protection alert" action="drop" reason="SERVER-OTHER Symantec MIME parser updateheader heap buffer overflow attempt" group="500" srcip="104.47.117.130" dstip="<local ip removed>" proto="6" srcport="65168" dstport="25" sid="39380" class="Attempted User Privilege Gain" priority="1" generator="1" msgid="0"

    As a work around I have configured an exception for Intrusion Prevention for any SMTP incoming traffic. Not perfect I know, but it is a work around that will get the email I need.

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