How Attackers Weaponized an Expired Discord Invite to Deliver Malware & Key Insights!
This week, we're exploring a recent campaign used by attackers to weaponize expired Discord invites to push malware. We’ll unpack the attack chain with key cybersecurity insights!
What do most successful attacks have in common?
They exploit something the victim ‘already’ trusts.
And here’s the thing — when we trust something, we rarely scrutinize it. Attackers know this all too well.
Today, I’m covering a campaign that I came across recently that weaponized expired Discord invite links to deliver malware. It’s a perfect example of how trust can become a weapon when a subtle design flaw meets a bit of social engineering.
First, a bit of context for those unfamiliar with Discord. Discord is a chat app where people can talk in real-time through text, voice, or video — kind of like Slack, but popular with communities and gamers. To join a server, someone usually shares an invite link — and here’s where the story begins.
🔍 The Attack Flow: A Step-by-Step Look
The attacker finds an invite link shared by a legitimate Discord community (e.g. https[:]//discord[.]com/asdfdsf4d).
Attacker waits until it expires > By default, Discord invite links are active for only 7 days.
Once it expires, attacker uses the 'custom invite' option in Discord that allows the user to manually type the invite code > Creates a new custom invite using the same expired code (i.e. asdfdsf4d in this case).
A user using the old invite link is now redirected to the attacker’s Discord server.
Upon joining, new members are asked to “verify” and are redirected to external website that mimics Discord UI.
Here's the interesting part: the fake page auto-copies a malicious PowerShell command to user's clipboard > Victim is instructed to paste and run it via Windows Run (aka "ClickFix" technique, see pic for clarity)
Once executed, the script installs RAT (Remote Access Trojan) > Gets full control of victim's machine.
💡Key Insights & Lessons
Bugs like this don’t stem from a technical security flaw. They stem from logical design gaps. These kinds of issues can't be caught by automated scanners because scanners lack 'intent awareness'.
Intent awareness is the ability to understand what a feature was meant to do and to recognize when its behavior can be abused in ways that go against that intention. In this case, the app allows reusing expired codes. A SAST scanner would look at this code and say "its clean". An intent-aware human would say "wait a second, this lets a stranger claim a code users already trust. That breaks the app’s trust model".
Maybe in the future, AI-driven tools will bridge this gap in the tools. But until then, plan wisely where you want to solely depend on scanners vs where you want to invest in manual pen-testing, threat modelling and code reviews.
This is a good example where AppSec meets Malware in the real world. In most security assessments, we stop at Step #4 and document the “potential risk” in a report. But attackers don’t theorize. They weaponize. And in the real world, practical risk always stretches far beyond perceived risk in ways we often don’t anticipate. A simple logical gap such as the ability to reuse expired invite codes is turned into a powerful attack vector when paired with a ClickFix-style social engineering trick.
Anytime you're generating a code (invites, password resets, magic links etc.) and using that code to grant some kind of access, you got to be cautious.
If that code can be reclaimed, re-registered, or misrouted, it opens up a dangerous trust gap. Expired doesn’t always mean its safe.