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It also solves the performance issue listed https://confluence.atlassian.com/display/JIRAKB/Anti-Virus+in+JIRA where JIRA users experience slowness due to scanning of temporary files.
When an attachment is added, a request is sent to scan the uploaded file. The request is handled asynchronously so that users need not wait for the scanning to completed especially if the file is large.
When a file is suspected to be infected, it will post a comment to the issue in the format "Filename" - "Alert Message". 
The user will receive a JIRA email notification of the comment to follow up.
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