Beyond the Green Dashboard: Are We Actually Validating Defenses?
Just saw the promo for the upcoming webinar on The Hacker News, Stop Guessing. Learn to Validate Your Defenses Against Real Attacks, and it really hit home.
It’s easy to get complacent when the SIEM is quiet and the AV dashboard is green. But "quiet" doesn't mean secure. I’ve been pushing my team to move away from assumption-based security and toward continuous validation (BAS/Purple Teaming). We recently tested our detection capabilities against Atomic Red Team tests for T1059.001 (PowerShell), and the results were... humbling.
We ran a simple obfuscation test to see if our EDR would catch basic execution bypass attempts:
# Test Command: Obfuscated PowerShell Execution
$Encoded = [System.Convert]::ToBase64String([System.Text.Encoding]::Unicode.GetBytes('Write-Host "Proof of Concept"'))
Start-Process -FilePath "powershell" -ArgumentList "-EncodedCommand $Encoded"
Surprisingly, our legacy rule set—which relied heavily on keyword matching for powershell.exe -enc—fired. However, when we shifted to using C:\Windows\System32\cmd.exe /c as the parent process, the alert was suppressed by a noise-reduction filter intended for administrators. We had essentially tuned ourselves blind to a valid execution chain.
Key Takeaway:
A control exists on paper, but is it effective in the pipeline?
- Detection Method: Ensure your SIEM rules correlate process ancestry, not just the command line arguments.
- Validation: Run these simulations monthly, not just during audits.
I’m curious how you all handle this. Are you relying on automated BAS platforms like Picus or SafeBreach, or are you running manual Purple Team exercises? What was the last "gap" that validation exposed in your environment?
We recently moved to a dedicated Purple Team schedule, and it’s been eye-opening. Like you, we found that our overly aggressive suppression lists were the culprit. We were missing C# payloads being executed via installutil.exe because we whitelisted the path years ago.
We started using the following KQL query to hunt for suspicious child processes of trusted binaries, which caught several false negatives:
ProcessCreationEvents
| where ProcessCommandLine contains "-enc" or ProcessCommandLine contains "-e "
| where ParentProcessName in~ ("cmd.exe", "powershell.exe", "rundll32.exe")
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, ParentProcessName
Validation isn't just a buzzword; it's the only way to trust your tech stack.
I’m in the MSP space, so I don't always have the budget for enterprise BAS tools. I rely heavily on open-source Atomic Red Team and mapping the results to the MITRE ATT&CK framework.
One major gap we found recently was with credential dumping. We assumed our EDR would block Mimikatz instantly. But when we tested ProcDump dumping the LSASS memory to disk for offline analysis, the alert didn't trigger until the file was touched by another process.
You can test this easily with:
.\procdump.exe -ma lsass.exe lsass.dmp
If your EDR isn't monitoring specifically for `lsass.exe` handle access or process dumps via `ProcDump`, you have a visibility gap regardless of your dashboard status.
Great post. The webinar topic is spot on. We often see 'configuration drift' where a sensor that was working perfectly during onboarding gets silently disabled or misconfigured during an update.
We’ve started implementing automated 'canary' tests—simple scripts that run every 4 hours to trigger a specific non-malicious but suspicious-looking alert (e.g., a specific registry key modification). If the alert doesn't hit the SOC within 5 minutes, we know the pipeline is broken. It's a crude form of validation, but it saves us from guessing.
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