yagbdb discord bot custom command to block image spambots

discord_anti_imagescams

{{/* === CONFIGURATION === */}}

{{/* where to log the action and deleted message */}}
{{$logChannel := 000000000000 }}
{{/* how often the same message needs to be sent in the timespan to trigger the command */}}
{{$triggerThreshold := 5 }}
{{/* the timespan between messages until they are no longer considered duplicates */}}
{{$duplicateTrackExpirationSeconds := 120 }}
{{/* how long to time out the offending user, blocks bots from spamming further */}}
{{$timeoutDurationMinutes := 300 }}


{{/* === SCRIPT START === */}}

{{/* DB keys for this user */}}
{{$userID := .User.ID}}
{{$counterKey := print "spamCounter:" $userID}}
{{$msgsKey := print "spamMsgs:" $userID}}


{{/* Fetch existing data */}}
{{$currentCounter := 0}}
{{with (dbGet $userID $counterKey)}}{{$currentCounter = .Value}}{{end}}

{{/* Add message to the stored list */}}
{{$existingMsgs := cslice}}
{{with (dbGet $userID $msgsKey)}}{{$existingMsgs = .Value}}{{end}}

{{$newMsg := dict "ID" .Message.ID "Content" .Message.Content "ChannelID" .Channel.ID}}
{{$updatedMsgs := $existingMsgs.Append $newMsg}}

{{/* Increase counter and reset DB expiration */}}
{{$newCounter := add $currentCounter 1}}
{{dbSetExpire $userID $counterKey $newCounter $duplicateTrackExpirationSeconds}}
{{dbSetExpire $userID $msgsKey $updatedMsgs $duplicateTrackExpirationSeconds}}

{{if ge (toInt $newCounter) $triggerThreshold}}

  {{try}}
    {{$noOutput := execAdmin "timeout" .User.Mention $timeoutDurationMinutes "Image Spam (Suspected Scambot)"}}
  {{catch}}
    {{sendMessage $logChannel (.Error) }}
  {{end}}

  {{/* Log the action */}}
  {{$logMsg := (printf "**Anti-Imagescam Triggered**\n\nUser: %s \nDeleting %d messages:\n\n" .User.Mention (len $updatedMsgs))}}
  {{/* Get the first message */}}
  {{$firstMsg := index $updatedMsgs 0}}
  {{$cleanContent := $firstMsg.Content}}
  {{$embed := cembed
    "description" (print $cleanContent)
    "color" 16711680
    "footer" (dict "text" (print "Triggered at: " currentTime))
    "author" (sdict
             "name" .User.Username
             "icon_url" (.Member.AvatarURL "256")
           )
   }}

  {{sendMessage $logChannel (complexMessage "content" $logMsg "embed" $embed)}}

  {{/* Delete all stored messages */}}
  {{range $msg := $updatedMsgs}}
    {{deleteMessage (toInt64 $msg.ChannelID) (toInt64 $msg.ID) 0}}
  {{end}}

  {{/* Clear user data after action */}}
  {{dbDel $userID $counterKey}}
  {{dbDel $userID $msgsKey}}

{{end}}

Setup

The custom command trigger is a Regex matching images hosted on discord: .*?(?:media|cdn)\.discord(app)?\.(?:net|com).*? but this can be adjusted on the fly if they ever swap to other hosting or generalised to get any image

Make sure to also set the $logChannel and ignore that channel in the command settings

Why?

This command specifically targets Discord spambots posting images to circumvent text automoderation

like this one

This can be complemented with this other automoderation rule in case they switch to directly uploading images to discord instead of sending links - those will actually be caught by the "with attachments" filter.

Notes

• The custom command matches image links because linked files are not considered attachments by discord
• The automod rule bans for one minute because message mass deletion is restricted to a single channel