Block image-based scam messages

[Zabuzard]

Summary

Closes #1278. Extends ScamBlocker to detect image-only scam messages, plus unit tests.

Details

As described in the ticket, messages are now flagged as scam if:

• empty message (isBlank())
• amount of suspicious attachments is greater than configed (suspiciousAttachmentsThreshold)
• an attachment is considered suspicious if it is an image (IsImage()) and its name matches the configured regex pattern suspiciousAttachmentNamePattern

The file name pattern is configured by default as desired in the ticket description. That is, it triggers on files like image.png or files with 1-2 digits like 1.jpg or 23.png.

Config

Added two new config params (part of "scamBlocker" config):

"suspiciousAttachmentsThreshold": 3,
"suspiciousAttachmentNamePattern": "(image|\\d{1,2})\\.[^.]{0,5}"

Impressions

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud