In the majority of popular messaging applications, spammer can add an individual to their group chat without requiring permission or a special hack, because two simple things exist:
1. Many groups are able to be joined publicly through either link or QR code.
2. The spammer will use one of these members of the group to generate numerous new invite links, effectively allowing them to remotely put themselves, and countless other accounts, into any group they desire.
How they do this:
1. Getting access to a group
a) Spammers will often create or purchase a cheap "burner" account from the Internet (most often, these will gladly sell previously compromised accounts for $0.10-$2).
b) They will find or purchase a public group invite link/QR code (from forums, Telegram, Discord servers, other dark-web markets, or through scraping social media).
2. Using the bot accounts they have created; the spammers will create/hire their bot accounts to execute the auto-join swarm (ie: having hundreds or thousands of bot accounts join a specific group in a matter of minutes).
a) They will use scripts/bots that are hosted on either their own cloud servers and/or infected computer(s), so that they may create/fill multiple bot accounts simultaneously.
b) Each time a new bot account is created and added to group, they can generate a new invite link (many applications allow this).
3. Exponential link generation
a) One account → generates link → adds 50 bots → those 50 bots each generate new links → repeat.
b) In just a few hours, it takes only one group of bots to create over 10,000 fake accounts on multiple social media platforms.
4. Spam / Payload Delivery in Mass Quantities
a) Bots create mass amounts of spam by sending out tons of phishing/ scam/ romance bait/ gift card refund pitch and banking Trojan droppers links to the group.
b) Swarm Effect - The spam will appear to be consistent with a true organic message as the messages will be sent from multiple social network profiles over a small time frame.
5. Self-Healing / Rotation
a) As soon as real users of the platform report the accounts, and the platforms ban the accounts, as many of the original bots are re-created using a different phone number, IP, and email ID to replace the banned account with fresh bots.
b) Spammers rotate their payloads and their personas (or accounts) to avoid detection by content filtering services provided by the social media platforms.
Top Ten Apps Commonly Used for Abuse
1. WhatsApp, The creation of the group is simple, creating a public invite link and not approving all members to gain access.
2. Telegram, Using a public group/ channel and creating unlimited invite links on each account.
3. Discord, Public invite links + auto-join bots very common in gaming/NFT/crypto servers.
4. Facebook Messenger Communities, Public join links still exist on many groups.
5. Viber & Signal, Less common but growing when public links are shared carelessly.
Why It Feels Like “No Permission Was Needed”
You didn’t give permission, but someone else in the group (often unknowingly) had a public invite link that the spammer obtained and exploited. Once the bots are inside, every new bot can invite more bots. The group owner/admins often don’t notice until thousands are already in and spamming starts.
Practical Protection Steps
1. Make every group private, WhatsApp/Telegram: Settings → Group settings → “Who can add members” → “Only admins”.
2. Disable Invite Links to the Public, Periodically Generate or Delete Outdated Link Invites.
3. Turn on "Approval for New Members" , Requires Approval from Club Manager before Joining, on WhatsApp or Telegram.
4. Check Your Participant List Regularly, If There Are Large Number of Unknown Users Entering Your Group, Leave or Report Group.
5. Mute and Store Groups Reported as Suspicious, Use WhatsApp's: Long Press on Group Name to Mute Notifications; Archive Groups
6. Report spam aggressively, Report messages → Report group → Block spam accounts. Platforms ban waves faster when many reports come in.
Key Takeaways
Spammers don’t hack your phone to add thousands to your group, they exploit public invite links and automated mass joining with cheap bot accounts. The weak point is almost always the group’s privacy settings or a leaked invite link.
Set every group to private, require admin approval for new members, and delete/regenerate invite links often. One simple setting change prevents almost all of this spam flood.
