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Exchange 2013 Spam in Queue for Citibank
Hi,
I'm having an issue with Microsoft Exchange and spam being sent from that server. I'm seeing tons of messages from alerts@citiybank.com going out to unsuspecting users across the web. Some of them have mx-b.mail.citi.com in the header.
Now I wasn't the one who setup this so I'm not sure how to find logs or whatever else you all might need to help isolate the issue. I've changed all of the passwords on my Domain and it's users and have tried to isolate one of the IP addresses I saw within the messages. That part has not worked.
Right now I'm being blocked from sending legitimate emails to gmail and yahoo.
I'm having an issue with Microsoft Exchange and spam being sent from that server. I'm seeing tons of messages from alerts@citiybank.com going out to unsuspecting users across the web. Some of them have mx-b.mail.citi.com in the header.
Now I wasn't the one who setup this so I'm not sure how to find logs or whatever else you all might need to help isolate the issue. I've changed all of the passwords on my Domain and it's users and have tried to isolate one of the IP addresses I saw within the messages. That part has not worked.
Right now I'm being blocked from sending legitimate emails to gmail and yahoo.
ExchangeEmail ServersEmail Clients
Last Comment
Mohammad Mahboob Rahmati
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ASKER
Let me restart that service now. I'm sure the machine was restarted recently.
ASKER
I've restarted the service but I still see a huge amount of spam messages going through.
Identity: Exchange\261934\6489695584
Subject: Suspicious Account Activity Reference q3SIzzS
Internet Message ID: <71d5a526a9324f96a1b483cd5
From Address: alerts-26fAzXY@citibank.co
Status: Ready
Size (KB): 40
Message Source Name: SMTP:Client Proxy
Source IP: 195.62.16.36
SCL: 0
Date Received: 3/17/2015 6:34:16 AM
Expiration Time: 3/19/2015 6:34:16 AM
Last Error:
Queue ID: Exchange\261934
Recipients: *****@aol.com;2;2;[{LRT=};
Identity: Exchange\261934\6489695584
Subject: Suspicious Account Activity Reference q3SIzzS
Internet Message ID: <71d5a526a9324f96a1b483cd5
From Address: alerts-26fAzXY@citibank.co
Status: Ready
Size (KB): 40
Message Source Name: SMTP:Client Proxy
Source IP: 195.62.16.36
SCL: 0
Date Received: 3/17/2015 6:34:16 AM
Expiration Time: 3/19/2015 6:34:16 AM
Last Error:
Queue ID: Exchange\261934
Recipients: *****@aol.com;2;2;[{LRT=};
ASKER
I've blocked traffic from 195.62.16.36 for now but I'm not sure if that will fix this issue.
ASKER
I'm also seeing this:
Identity: Exchange\261911\6490554577
Subject: Undeliverable: Suspicious Account Activity Reference h7dAoVu
Internet Message ID: <b53c0dac-aad7-4018-9f56-9
From Address: <>
Status: Ready
Size (KB): 40
Message Source Name: DSN
Source IP: 255.255.255.255
SCL: -1
Date Received: 3/17/2015 8:55:46 AM
Expiration Time: 3/19/2015 8:55:46 AM
Last Error:
Queue ID: Exchange\261911
Recipients: alerts-KTN6R0z@citibank.co
Identity: Exchange\261911\6490554577
Subject: Undeliverable: Suspicious Account Activity Reference h7dAoVu
Internet Message ID: <b53c0dac-aad7-4018-9f56-9
From Address: <>
Status: Ready
Size (KB): 40
Message Source Name: DSN
Source IP: 255.255.255.255
SCL: -1
Date Received: 3/17/2015 8:55:46 AM
Expiration Time: 3/19/2015 8:55:46 AM
Last Error:
Queue ID: Exchange\261911
Recipients: alerts-KTN6R0z@citibank.co
Restarting the service will not clear the problem.
All it will do is stop new messages from being delivered to the server.
Furthermore the post you have put above is an NDR. Do you have recipient filtering enabled on the server? If not then you should enable it, as it will stop the server being abused with NDR spam.
When you have had something like this happen, the first thing you have to do is stop new emails. You can now look at clearing the queues of those messages.
Simon.
All it will do is stop new messages from being delivered to the server.
Furthermore the post you have put above is an NDR. Do you have recipient filtering enabled on the server? If not then you should enable it, as it will stop the server being abused with NDR spam.
When you have had something like this happen, the first thing you have to do is stop new emails. You can now look at clearing the queues of those messages.
Simon.
ASKER
I've cleared the queue numerous times. And I don't know how to enable recipient filtering.
Due to the way that Exchange processes emails, it can take a number of attempts to completely clear the queues.
When a spammer manages to compromise a server they will dump 1000s of messages on the server. Remember you are seeing just the failed messages, many more will have been delivered.
Recipient filtering is part of the anti spam agents.
This is the TechNet guide on installing the agents:
https://technet.microsoft.com/en-us/library/bb201691(v=exchg.150).aspx
Then enable it thus:
Set-RecipientFilterConfig -Enabled $true
Restart Transport again once you have done so.
Simon.
When a spammer manages to compromise a server they will dump 1000s of messages on the server. Remember you are seeing just the failed messages, many more will have been delivered.
Recipient filtering is part of the anti spam agents.
This is the TechNet guide on installing the agents:
https://technet.microsoft.com/en-us/library/bb201691(v=exchg.150).aspx
Then enable it thus:
Set-RecipientFilterConfig -Enabled $true
Restart Transport again once you have done so.
Simon.
ASKER
Where could I see the messages that are going out? A log? If so where do I enable and see that?
ASKER
Also, for the Set-Recipient command....
WARNING: The command completed successfully but no settings of 'RecipientFilterConfig' have been modified.
WARNING: The command completed successfully but no settings of 'RecipientFilterConfig' have been modified.
That would suggest that you already had the setting enabled.
You may want to do a telnet test to confirm that an email to an unknown recipient is being rejected.
Messages going out are not logged by default, other than what you can get on Message Tracking. You can enable logging on the connectors, but they will generate large amounts of logs if you aren't careful.
Simon.
You may want to do a telnet test to confirm that an email to an unknown recipient is being rejected.
Messages going out are not logged by default, other than what you can get on Message Tracking. You can enable logging on the connectors, but they will generate large amounts of logs if you aren't careful.
Simon.
ASKER
Ok I need to know how to enable this, at least for a few minutes. Remember, I'm not very familiar with how Exchange works so please give as detailed information as possible. Thank you
Logging is enabled on the properties of the Send and Receive connectors within ECP.
After enabling it you need to restart Exchange Transport service for the change to take effect.
The location of the logs is set on the properties of the server in ECP, under Transport Logs.
Simon.
After enabling it you need to restart Exchange Transport service for the change to take effect.
The location of the logs is set on the properties of the server in ECP, under Transport Logs.
Simon.
please check the properties of the receive connectors: Default Exchange server and Default Frontend Server, on Security, check if Anonymous is checked, and if yes, uncheck it. After that you have to restart the Microsoft Exchange transport and the Microsoft Exchange Frontend Transport services to apply it.