The MSP Security Gap
The message came from inside Teams
The scenario:
A Teams message pops up for your client’s office manager. “IT Support” with a familiar-looking logo: “We’re migrating mailboxes tonight, run the attached update to keep access.”
It is inside Teams, so it feels internal. Email suspicion took a decade to train into staff. Nobody trained them on chat.
How it unfolds:
The message came from an external tenant, named to look like support. External federation was on by default, so a stranger reached staff directly inside the tool they trust most.
The attached “update” is a loader. One employee runs it, and the attacker has a foothold on a managed endpoint, inside a session the security stack considers normal.
Variants of the same play: a fake CEO account asking finance for a call, a “vendor” sharing a SharePoint link that harvests credentials, a compromised partner tenant messaging genuinely from a real company.
Chat earned trust faster than any channel business uses, and attackers moved there for that reason. The training gap does the rest: staff who forward every odd email to the desk will run a file from Teams without blinking, because nobody told them the doubt applies there too.
The warning signs:
Any external-tenant message claiming to be internal IT.
Urgency plus a file or a link inside chat.
A name you know with a tenant domain you do not.
Requests moving you off the ticket system into a private chat.
Stop it:
Restrict external federation: allowlist the partner tenants that need chat access, block the rest.
Label external messages loudly, and teach staff the label means the sender is outside the company whatever the display name says.
One rule for staff: IT never sends executables through chat. Anything claiming otherwise goes to the desk.
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P.S. Chat platforms sit outside most email security entirely. The message arrives, the file runs, and the first thing your stack sees is the process starting on the endpoint. Catching it there, before it moves, is the whole game.
Patch first this week:
This week’s KEV additions, ranked by what MSPs run across client fleets. Verified against NVD, CISA, and vendor advisories.
• Cisco Secure Firewall ASA and FTD CVE-2026-20349 (8.6)
A flaw in the Remote Access SSL VPN service lets an unauthenticated attacker send a crafted HTTP request and force the device to reload. No credentials, no foothold, no malware. The firewall simply goes down, and it goes down again when the request is sent again. Cisco attributes it to insufficient error checking when processing HTTP requests.
Who runs it: any client where a Cisco ASA or FTD terminates remote access VPN, which in most MSP fleets means the sites that matter most. This is denial of service rather than code execution, so it will not show up as a breach. It will show up as an outage you cannot explain to a client at 9am.
Fix: apply the update in Cisco advisory cisco-sa-asaftd-vpn-dos-dzv4mQFF. KEV August 11. Federal deadline August 14. Where the maintenance window cannot be found this week, restrict which source addresses can reach the Remote Access SSL VPN listener.
• Progress LoadMaster CVE-2026-8037 (9.8)
Unauthenticated OS command injection in the API. Unsanitized input across several command endpoints runs as root on the appliance. Progress patched it on June 4, exploitation attempts began in late June once public research landed, and CISA moved it to KEV on August 7 after evidence of active targeting.
Who runs it: clients with Kemp or LoadMaster load balancers in front of web applications, plus anyone running ECS Connection Manager, Connection Manager for ObjectScale, or MOVEit WAF, which share the same code.
Affected: LoadMaster below 7.2.54.18 on the long term support line, and 7.2.55.0 up to 7.2.63.2 on the general line.
Fix: 7.2.63.2 or 7.2.54.18. KEV August 7. Federal deadline August 10, passed. If the appliance was internet facing and unpatched since June, assume the patch is step one and not the whole job. Check administrative accounts and scheduled tasks on the appliance before you close the ticket.
• Microsoft Windows Ancillary Function Driver for WinSock CVE-2026-68820 (7.0)
A use after free in afd.sys that lets an attacker who already has a local account raise privileges. This is the driver that has carried exploited elevation bugs repeatedly, and the pattern holds: it is the second half of an intrusion, not the way in. Phishing gets the user account, this turns it into SYSTEM.
Who runs it: every Windows machine you manage. Fix shipped with the August 11 updates, so this one is patch management rather than a special project. KEV August 11. Federal deadline August 25, the longest runway on the list, which reflects fleet size rather than low risk. If a client is behind on the July rollup, this is the argument for catching up now.
• Metabase CVE-2026-72898 (10.0)
A remote unauthenticated attacker injects SQL through the reset_password endpoint and gains administrator access to the Metabase instance and the databases wired into it. A 10.0 with no authentication and a business intelligence tool that by design holds credentials for production data sources.
Who runs it: clients who stood up Metabase for reporting, usually the finance or operations team rather than IT, which is why it rarely appears on an asset list.
Affected and fixed: upgrade to 58.24, 59.21, 60.17, 61.11, 62.9, or 63.5 depending on the line you are on. KEV August 11. Federal deadline August 14. If you find one, check whether the instance is reachable from the internet and what database credentials it holds before you patch, because those credentials should be treated as exposed.