Getting Spam Posts

[soruntu]

Dear All,

My system is getting spam issues on my system.

So I am getting below messages.

There is no username as a USER

Thanks,

Reported By: User
Assigned To: User
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Project: IT & System
Issue ID: 110
Category: Urgency
Reproducibility: always
Severity: minor
Priority: high
Status: new
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Date Submitted: 2014-06-23 13:49 CEST
Last Modified: 2014-06-23 13:49 CEST
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Summary: your server is attacked. "Alert !! Alert !!"
Description:
your server is attacked.
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Issue History
Date Modified Username Field Change
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2014-06-23 13:49 User New Issue
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[atrol]

Hard to help as you did not write anything about your system, your configurations, ...

Which versions of MantisBT do you use?
Have you enabled anonymous accounts?
Do you allow signup, if yes, have you enabled captcha?
...