If your software deployment suddenly stopped working and you found out your antivirus was the culprit, don’t panic — you’re not alone. Many IT teams experienced headaches when Sophos Endpoint decided to block even trusted, signed installer packages. But there’s a happy ending, and we’ll walk you through what happened, why it happened, and how a magical little policy exception brought deployments back to life.
TL;DR
Sophos Endpoint Protection recently started blocking signed installer packages, flagging them as threats. This disrupted software deployment workflows. The issue was due to an over-aggressive detection rule. A policy exception rule was then added to fix the problem and restore normal operations.
What Is Sophos Endpoint?
Let’s start with the basics. Sophos Endpoint is antivirus and endpoint security software used by businesses to protect devices against malware, ransomware, and other shady stuff. It’s like a digital security guard watching everything that runs on your computer.
Usually, that’s great! But sometimes the guard gets a little overprotective…
Wait, Signed Installers Got Blocked?
Yep! Here’s where things got weird. At some point, Sophos Endpoint Protection became suspicious of even signed installer files. These are packages that come from verified software vendors. They have digital certificates that say, “Hey, I’m safe!”
But Sophos didn’t agree. It started blocking these files during deployments — installers from trusted vendors like Microsoft, Adobe, and even homegrown company tools.
Imagine you’re trying to install Microsoft Teams over your network, and suddenly, Sophos jumps in like:
“Nope! This is dangerous!”
Why Did Sophos Do That?
It turns out a policy tweak or an update in Sophos’s detection rules caused the antivirus engine to treat certain installer behavior as dangerous — even when those files were valid and verified.
Sophos looks at file behavior, not just signatures. If something starts writing to system files or launching child processes in a certain way, Sophos might see red flags.
This is usually a good way to catch malware pretending to be good software, but in this case? False positives everywhere.
The Emergency Meetings Begin…
Admins across offices were scratching their heads (and maybe yelling a little).
- “Why is our Zoom installer getting blocked?”
- “Why won’t Visual Studio deploy to new machines?”
- “Who broke our deployment scripts???”
Once people figured out Sophos was the blocker, the online forums lit up. IT teams started disabling Sophos temporarily just to get deployments done. Not a safe move — but hey, desperate times!
The Magical Fix: A Policy Exception Rule
Soon after, Sophos heard the noise. Their team worked fast. The solution? A Policy Exception. This lets you tell Sophos, “Hey, trust this file. Chill out.”
You can set exceptions based on:
- File hash
- Path
- Certificate signer name
For signed installer packages, the magic lay in allowing trusted signers. So, Sophos rolled out an update or let admins add exceptions manually based on certificate trust.
Once the exception was added, Sophos stopped treating the signed installers like villains. Deployments started working again. IT folks rejoiced. Coffee mugs were raised.
How to Add an Exception (Simple Steps)
Adding a policy exception in Sophos Central is easy. Here’s how you do it:
- Log into your Sophos Central Admin dashboard.
- Go to Global Settings > Global Exclusions.
- Click Add Exclusion.
- Select the type (e.g., Certificate, File, Folder).
- Paste or browse to your trusted item.
- Save and apply changes.
Make sure you only whitelist trusted files and publishers. Whitelisting the wrong thing defeats the purpose of antivirus!
Lessons Learned
This incident taught us a few good lessons:
- Security software can overreact. Be alert and ready for false positives.
- Monitoring forums helps. You find answers quicker when everyone’s talking.
- Know your tools. Learning how to make policy exceptions is a lifesaving skill for IT admins.
- Signed ≠ always safe. Just because something is signed doesn’t mean it’s clean. But in this case, it was Sophos being too careful.
What You Can Do to Stay Prepared
Here are some best practices so you’re not caught flat-footed next time:
- Test updates and deployments in a safe environment before rolling them out company-wide.
- Subscribe to your software vendors’ update emails — quick bug fixes and advisories can save you!
- Regularly review and update your security exceptions.
- Keep in touch with your antivirus vendor’s support team. They can provide pre-configured exclusions if needed.
The Bottom Line
Sophos Endpoint is powerful and usually reliable. But no security tool is perfect. Even the best systems can sometimes shoot the good guys by mistake. The key is knowing when and how to step in.
Signed installer packages getting blocked was frustrating, but thanks to quick response from security teams and some smart policy rules, things are back on track. So next time your deployments stall out, don’t panic — check with your endpoint protector first.
And always, always, keep your coffee mug full. IT problems never wait for your break time.